Graphene-based nanostructures with distinct structural and physicochemical characteristics may be able to photodegrade antibiotics effectively. Herein, this study reports the successful synthesis of NiFe2O4/CeO2/GO nanocomposite (NC) by anchoring NiFe2O4/CeO2 to the surface of GO (Graphene oxide). All state-of-the-art characterization techniques investigated the nanostructure, crystallinity, phonon modes, chemical composition analysis, elemental composition, surface area, magnetic properties, and optical band gap. Hydrothermal approach assisted NiFe2O4/CeO2/GO catalyst showed better charge carrier separation and prompted the tetracycline (TC-HCl) photocatalytic degradation under visible light. Following 90 minutes of exposure to visible light, NiFe2O4/CeO2/GO nanocomposite demonstrated superior photocatalytic activity, with a TC-HCl degradation rate of 95%. Reasonable mechanisms of tetracycline degradation were proposed where the OH and O played a leading role based on identified intermediates. Moreover, tetracycline photodegradation intermediates and the optimal pathway were identified using LC-MS spectrometry. This study also performed Density Functional Theory (DFT) calculations for the prepared materials to validate the experimental data. In vitro, antibacterial studies were consistent with the molecular docking investigations of the NiFe2O4/CeO2/GO nanocomposite against DNA gyrase and FabI from Escherichia coli (E. coli) and Staphylococcus aureus (S.aureus). Lastly, the outcomes revealed a new potential for NiFe2O4/CeO2/GO nanocomposite for improved photocatalytic performance, making it a promising photocatalyst for wastewater treatment.

Highly accurate force fields are a mandatory requirement to generate predictive simulations. In this regard, Machine Learning Force Fields (MLFFs) have emerged as a revolutionary approach in computational chemistry and materials science, combining the accuracy of quantum mechanical methods with computational efficiency orders of magnitude superior to ab-initio methods. This chapter provides an introduction of the fundamentals of learning and how it is applied to construct MLFFs, detailing key methodologies such as neural network potentials and kernel-based models. Emphasis is placed on the construction of SchNet model, as one of the most elemental neural network-based force fields that are nowadays the basis of modern architectures. Additionally, the GDML framework is described in detail as an example of how the elegant formulation of kernel methods can be used to construct mathematically robust and physics-inspired MLFFs. The ongoing advancements in MLFF development continue to expand their applicability, enabling precise simulations of large and complex systems that were previously beyond reach. This chapter concludes by highlighting the transformative impact of MLFFs on scientific research, underscoring their role in driving future discoveries in the fields of chemistry, physics, and materials science.

We present a theory of spin-polarized superconductivity from the condensation of excitonic Cooper pairs, which are charge-$2e$ bosonic quasiparticles made of Cooper pairs strongly hybridized with excitons. By solving a model of spin-polarized electrons using the strong-coupling expansion to the second order, we demonstrate the emergence of excitonic Cooper pairs from electron-hole fluctuations upon doping a strongly correlated insulator. We characterize their binding energy, effective mass, and the resulting superconducting transition temperature. We propose possible realization of spin-polarized superconductivity in twisted semiconductors with honeycomb moir\'e superlattice.

Recently, it has been established that Chern insulators possess an intrinsic two-dimensional electric polarization, despite having gapless edge states and non-localizable Wannier orbitals. This polarization, $\vec{P}_{\text{o}}$, can be defined in a many-body setting from various physical quantities, including dislocation charges, boundary charge distributions, and linear momentum. Importantly, there is a dependence on a choice of real-space origin $\text{o}$ within the unit cell. In contrast, Coh and Vanderbilt extended the single-particle Berry phase definition of polarization to Chern insulators by choosing an arbitrary point in momentum space, $\vec{k}_0$. In this paper, we unify these two approaches and show that when the real-space origin $\text{o}$ and momentum-space point $\vec{k}_0$ are appropriately chosen in relation to each other, the Berry phase and many-body definitions of polarization are equal.

We study the formation of subgap impurity states in strongly correlated Mott insulators. We use a composite operator method that gives us access to both the bulk Green's function, as well as to the real-space Green's function in the presence of an impurity. Similar to the non-interacting systems, we show that the formation of impurity subgap states at large impurity potential ("Mott ring states") depends rather on the band-mixing, than on the topological character of the system. Thus even a trivial Mott insulator can under certain conditions exhibit ring states. For the system studied here the band mixing is that between the holon and doublon elementary excitations rather than an orbital mixing. Moreover we study the formation of bands of zeros in the correlated Green's function, believed to exhibit a free quasiparticle-like behavior. We show that in the presence of an impurity the same conclusion can be applied, i.e. ``Mott zeros ring states" form in the presence of topological bands of zeros, but also for trivial quasi-flat bands of zeros with band mixing.

We use experiments and theory to elucidate the size effect in capillary breakup rheometry, where pre-stretching in the visco-capillary stage causes the apparent relaxation time to be consistently smaller than the actual value. We propose a method accounting for both the experimental size and the finite extensibility of polymers to extract the actual relaxation time. A phase diagram characterizes the expected measurement variability and delineates scaling law conditions. The results refine capillary breakup rheometry for viscoelastic fluids and advance the understanding of breakup dynamics across scales.

Phonon interactions from lattice anharmonicity govern thermal properties and heat transport in materials. These interactions are described by $n$-th order interatomic force constants ($n$-IFCs), which can be viewed as high-dimensional tensors correlating the motion of $n$ atoms, or equivalently encoding $n$-phonon scattering processes in momentum space. Here, we introduce a tensor decomposition to efficiently compress $n$-IFCs for arbitrary order $n$. Using tensor learning, we find optimal low-rank approximations of $n$-IFCs by solving the resulting optimization problem.Our approach reveals the inherent low dimensionality of phonon-phonon interactions and allows compression of the 3 and 4-IFC tensors by factors of up to $10^3-10^4$ while retaining high accuracy in calculations of phonon scattering rates and thermal conductivity. Calculations of thermal conductivity using the compressed $n$-IFCs achieve a speed-up by nearly three orders of magnitude with >98\% accuracy relative to the reference uncompressed solution. These calculations include both 3- and 4-phonon scattering and are shown for a diverse range of materials (Si, HgTe, MgO, and TiNiSn). In addition to accelerating state-of-the-art thermal transport calculations, the method shown here paves the way for modeling strongly anharmonic materials and higher-order phonon interactions.

We report the formation of a $\mathbb{Z}_2$ vortex crystal in the tetrahedral antiferromagnetic order on a triangular lattice. The noncoplanar tetrahedral state consists of four sublattices with spins oriented along the faces of a tetrahedron in spin space. The long-range order characterized by a $\mathbb{Z}_2$ topology arises due to the Dzyaloshinskii-Moriya interaction and appears at zero temperature and without external fields. The $\mathbb{Z}_2$ vortex crystal is composed of four interpenetrating skyrmion-like topological defects. Its magnetic excitations include magnetically active gyrotropic and breathing modes, which -- under an external magnetic field -- carry nontrivial Chern numbers that stabilize chiral magnon edge states.

The evolution of the role of lattice vibrations in the formation of the pseudogap state in strongly correlated electron systems has been investigated concerning changes in the electron-phonon coupling parameters and the concentration of doped charge carriers. We apply the polaronic version of the generalized tight-binding method to analyze the band structure of a realistic multiband two-dimensional model that incorporates the electron-lattice contributions of both Holstein and Peierls types. It has been demonstrated that the emergence of polaronic effects begins with the modulation of spectral function intensity. However, within a specific region of the phase diagram, a significant transformation of the electron band structure and pseudogap state occurs. It results from coherent polaron excitations that create a partially flat band near the Fermi level. This process leads to a change in the topology of the Fermi surface and the emergence of corresponding features in the density of states.

A nonlinear continuum theory is advanced for high-rate mechanics and thermodynamics of liver parenchyma. The homogenized continuum is idealized as a solid-fluid mixture of dense viscoelastic tissue and liquid blood. The solid consists of a matrix material comprising the liver lobules and a collagenous fiber network. Under high loading rates pertinent to impact and blast, the velocity difference between solid and fluid is assumed negligible, leading to a constrained mixture theory. The model captures nonlinear isotropic elasticity, viscoelasticity, temperature changes from thermoelasticity and dissipation, and tissue damage, the latter via a scale-free phase-field representation. Effects of blood volume and initial constituent pressures are included. The model is implemented in 3-D finite element software. Analytical and numerical solutions for planar shock loading are compared with observations of liver trauma from shock-tube experiments. Finite-element simulations of dynamic impact are compared with cylinder drop-weight experiments. Model results, including matrix damage exceeding fiber damage at high rates and reduced mechanical stiffness with higher perfused blood volume, agree with experimental trends. Viscoelasticity is important at modest impact speeds.

Experimental, theoretical, and numerical studies of adiabatic shear in ductile metals suggest initial defects such as pores or material imperfections increase shear-band susceptibility. Conversely, viscous effects manifesting macroscopically as strain-rate sensitivity inhibit localization. The analytical shear-band process zone model due to D.E. Grady, in turn based on a rigid-plastic solution for stress release by N.F. Mott, is advanced to account for these phenomena. The material contains an average defect measure (e.g., porosity) and a concentrated defect measure at a spatial location where shear banding is most likely to initiate after an instability threshold is attained. Shearing resistance and certain physical properties are reduced commensurately with local defect concentration. Non-Newtonian viscosity increases dissipative resistance. Viscous dissipation, if strong enough, is shown to prevent an infinitesimal-width shear band even in a non-conductor. Here, a pseudo-quadratic viscosity widens the band similarly to heat conduction, and akin to quadratic shock viscosity often used to resolve widths of planar shock waves. The model captures simulation data showing reduced localization strain and shear band width with increasing maximum initial pore size in additively manufactured titanium and HY-100 steel. Predictions for shear band width, local strain, and temperature are more accurate versus data on steel than prior analytical modeling. A quantitative framework is established by which processing defects can be related to shear-banding characteristics.

The metal-insulator transition (MIT) in rare-earth nickelates exemplifies the intricate interplay between electronic correlations and lattice dynamics in quantum materials. This work focuses on SmNiO3 as a prototypical system, employing molecular dynamics simulations based on a "hidden" magnetic potential model. Our simulations reveal two key findings. First, the structural phase transition in SmNiO3 is intrinsically temperature-driven and occurs spontaneously via collective lattice distortions. Moreover, systematic high-pressure simulations demonstrate a distinct pressure dependence of the transition temperature, which decreases monotonically with increasing external hydrostatic pressure. These results provide atomistic insights into the cooperative mechanisms underlying the MIT and the interplay between structural distortions and electron correlation effects. The computational approach developed herein offers a generalizable framework for investigating complex phase transitions in correlated quantum materials.

Magnetic systems with noncentrosymmetric crystal structures are renowned for their complex magnetic ordering and diverse and fascinating physical properties. In this report, we provide a comprehensive study of the chiral magnetic system Ni$_2$ScSbO$_6$, which exhibits a robust incommensurate long-range antiferromagnetic spin ordering at a temperature of $T_N = 62$~K, as revealed by bulk magnetization, specific heat, and neutron diffraction studies. This magnetic ordering triggers a series of intriguing phenomena, including prominent magnetodielectric coupling manifested by a dielectric peak at $T_N$, significant spin-phonon coupling resulting in strong phonon renormalization characterized by anomalous softening of various Raman modes, and a remarkable volume magnetostriction effect probed by high-resolution synchrotron X-ray diffraction. These phenomena are intricately interlinked, positioning the present system as a rare and interesting material.

The intrinsic magnetic topological material MnBi2Te4 has demonstrated great potential to investigate the interplay between topology and magnetism, which opens up new avenues for manipulating non-trivial electronic states and designing quantum devices. However, challenges and controversies remain due to its inevitable n-type antisite defects, hindering the experimental realization of intrinsic magnetic topological phenomena and rendering the precise control of topological phase transitions (TPTs) unachievable. Here, we study a candidate material family, Mn(1-x)GexBi2Te4, in which the heavy n-type doping features are strongly suppressed when the Ge content reaches 0.46, and multiple topological phases are well maintained with the surface Dirac point located near the Fermi level. Based on angle-resolved photoemission spectroscopy, transport measurements, and first-principles calculations, we reveal two magnetism-induced TPTs: the first is antiferromagnetic-ordering-induced transition from strong topological insulator to a magnetic topological insulator as revealed by gap opening of topological surface states; the second is external-magnetic-field-dependent transition from magnetic topological insulator to a Weyl semimetal with the gap reclosed. Our work paves the way for the realization of intrinsic magnetic topological states in MnBi2Te4 family and provides an ideal platform for achieving controllable and continuous TPTs towards future spintronic applications.

Wrinkling is commonly observed as mechanical instability when a stiff thin film bound on a compliant thick substrate undergoes in-plane compression exceeding a threshold. Despite significant efforts to create a broad range of surface patterns via wrinkling, little has been studied about a dynamic and transient wrinkling process, where a suspended polymer thin film undergoes liquid-to-solid phase transitions. Here, a spontaneous wrinkling process is reported, when drying poly(vinyl alcohol) (PVA) soap films suspended on 3D printed wireframes with near zero or negative Gaussian curvatures. As water evaporates, a thickness gradient across the sample is developed, leading to non-uniform drying rates, and a concentration gradient between the inner and outer sides (exposed to air) of the suspended PVA soap film induces a differential osmotic pressure. Together, these effects contribute to an in-plane compressive stress, leading to the formation of surface wrinkles, whose growth is guided by the geometry of the frame. Importantly, the wrinkles evolve dynamically: the wavelength and number of the wrinkles can be tuned by altering the concentration of the PVA aqueous solutions, the initial mass, the relative humidity of the drying environment; the patterns of the resulting wrinkles can be programmed by the geometry of the wireframe.

Aging limits commercial lithium-ion battery lifetime and must be understood at the level of active materials to improve both cell durability and performance. We show that in state-of-the-art technologies such as graphite/LiFePO4-Li(NiCoAl)O2 cells, degradation mostly arises at the negative electrode side due to both loss of active material and cyclable lithium. The characteristics of these phenomena are unraveled by applying a multi-technique workflow in which electrochemical, structural, and morphological analyses are combined. Series of post mortem, ex situ and operando experiments performed on aged materials dismounted from a large format cell at its end-of-life are benchmarked against pristine materials to highlight how in-plane and through-plane heterogeneities in graphite dynamics are profoundly modified in nature and exacerbated by aging. We discover inactive regions, where pure graphite or lithiated phases (LixC6) are invariant on cycling. They correspond to particles either disconnected (irreversibly lost) or kinetically-limited (reactivated at a very slow C-rate). As we map their distribution in 2D during battery cycling, we observe that LixC6-inactivity is heterogeneously distributed in the depth of the aged negative electrode and depends on both the x value and the C-rate. In particular, the negative electrode-separator interface is much more inactivated after long-term usage. Inactivity is correlated with an overall increased spatial heterogeneity of lithium concentration. This work suggests that the origin of aging lies in overworking graphite close to the separator.

Quantum heat engines have undergone extensive studies over the last two decades. Simultaneously, the studies of the applications of stochastic resetting in various fields are on the rise. We explore the effect of stochastic resetting on the dynamics of a two-level and a three-level quantum heat engine. The extracted work is shown to increase with the resetting rate. However, the effective efficiency that includes the work expended in resetting is shown to exhibit a steady decay with the increase in resetting rate. The efficient power is observed to increase beyond that obtained in the absence of resetting, and is shown to be higher for a three-level engine.

When the center of fluctuations, i.e., the nonequilibrium eigenphase, undergoes transformation, there emerge critical parameters that demonstrate insensitivity to fluctuation perturbations and even independence from the molecular physical properties of the system, while exhibiting pronounced efficacy in governing phase transition dynamics.In the context of polymer glass transitions, Flory's conjecture (or C1 in the WLF equation) represents such a longstanding yet unresolved critical parameter. To address this issue, we replace entropy variation with a sequence of microstates and provide an analytically tractable statistical description of non-ergodicity. Our theory rigorously demonstrates that reaching the critical parameter is a necessary condition for non-equilibrium transitions to occur. Due to correlations between the eigenphase's entropy and energy in non-equilibrium systems, any system with a given intrinsic structure inherently possesses a critical parameter that represents the limiting deviation from equilibrium at any temperature. Flory's conjecture exemplifies this, with our new theoretical critical void ratio at the glass transition boundary calculated to be 2.6%, which closely matches experimental observations of 2.5%-2.6% over the past 50 years.

Skyrmions, topologically protected textures, have been observed in different fields of nanotechnology and have emerged as promising candidates for different applications due to their topological stability, low-power operation, and dynamic response to external stimuli. First introduced in particle physics, skyrmions have since been observed in different condensed matter fields, including magnetism, ferroelectricity, photonics, and acoustics. Their unique topological properties enable robust manipulation and detection, paving the way for innovative applications in room temperature sensing, storage, and computing. Recent advances in materials engineering and device integration have demonstrated several strategies for an efficient manipulation of skyrmions, addressing key challenges in their practical implementation. In this review, we summarize the state-of-the-art research on skyrmions across different platforms, highlighting their fundamental properties and characteristics, recent experimental breakthroughs, and technological potential. We present future perspectives and remaining challenges, emphasizing the interdisciplinary impact of skyrmions on nanotechnology.

We present a quantum response approach to momentum-space gravity in dissipative multiband systems, which dresses both the quantum geometry--through an interband Weyl transformation--and the equations of motion. In addition to clarifying the roles of the contorsion and symplectic terms, we introduce the three-state quantum geometric tensor and discuss the significance of the emergent terms from a gravitational point of view. We also identify a dual quantum geometric drag force in momentum space that provides an entropic source term for the multiband matrix of Einstein field equations.

In recent years, the nonlinear anomalous thermal Hall effect has attracted substantial attention. In this paper, we carry out a theoretical exploration of the intrinsic anomalous thermal Hall and Nernst effect that is induced by the thermal Berry connection polarizability. This effect is independent of the relaxation time and can be present in antiferromagnets possessing PT symmetry. Additionally, we put forward a second-order intrinsic Wiedemann-Franz law, which represents the ratio of the second-order intrinsic thermal conductivity coefficient to the second-order intrinsic electrical conductivity coefficient . When analyzed within a four-band PT symmetric Dirac model, we observe that the second-order intrinsic thermal conductivity coefficient is linearly proportional to the second-order intrinsic electrical conductivity coefficient , and the second-order intrinsic Wiedemann-Franz law is characterized by the chemical potential $\mu$ in the low-temperature regime. These findings provide significant implications for experimental verification.

We consider the dynamics of pore-driven polymer translocation through a nanopore to semi-infinite space when the chain is initially confined and equilibrated in a narrow channel. To this end, we use Langevin dynamics (LD) simulations and iso-flux tension propagation (IFTP) theory to characterize local and global dynamics of the translocating chain. The dynamics of the process can be described by the IFTP theory in very good agreement with the LD simulations for all values of confinement in the channel. The theory reveals that for channels with size comparable to or less than the end-to-end distance of the unconfined chain, in which the blob theory works, the scaling form of the translocation time depends on both the chain contour length as well as the channel width. %originating from the confinement of the spatial fluctuations of the chain inside the channel. Conversely, for a very narrow channel the translocation time only depends on the chain contour length and is similar to that of a rod due to the absence of spatial chain fluctuations.

We investigate the shrinkage induced breakup of thin layers of heterogeneous materials attached to a substrate, a ubiquitous natural phenomenon with a wide range of potential applications. Focusing on the evolution of the fragment ensemble, we demonstrate that the system has two distinct phases: damage phase, where the layer is cracked, however, a dominant piece persists retaining the structural integrity of the layer, and a fragmentation phase, where the layer disintegrates into numerous small pieces. Based on finite size scaling we show that the transition between the two phases occurs at a critical damage analogous to continuous phase transitions. At the critical point a fully connected crack network emerges whose structure is controlled by the strength of adhesion to the substrate. In the strong adhesion limit, damage arises from random microcrack nucleation, resembling bond percolation, while weak adhesion facilitates stress concentration and the growth of cracks to large extensions. The critical exponents of the damage to fragmentation transition agree to a reasonable accuracy with those of the two-dimensional Ising model. Our findings provide a novel insights into the mechanism of shrinkage-induced cracking revealing generic scaling laws of the phenomenon.

Ultrathin ferroelectric films with out-of-plane polarization and high Curie temperatures are key to miniaturizing electronic devices. Most ferroelectrics employed in devices are proper ferroelectrics, where spontaneous polarization is the primary order parameter. Unfortunately, the Curie temperature of proper ferroelectrics is drastically reduced as the ferroelectric becomes thin; nearly all proper ferroelectrics need to be thicker than several unit cells. The absence of an ultrathin limit has been predicted, but not verified for improper ferroelectrics. These are ferroelectrics where the polarization emerges secondary to the primary order parameter, such as a structural distortion. Here we report improper ferroelectricity with an undiminished Curie temperature in a 0.75-unit-cell-thick hexagonal LuFeO3 (h-LuFeO3) film grown on a SrCo2Ru4O11 bottom electrode with an atomically engineered monolayer bridging layer. Our results demonstrate the absence of a critical thickness for improper ferroelectricity and provide a methodology for creating ultrathin improper ferroelectrics by stabilizing their primary order parameters.

Single-atom catalysts (SACs) have attracted ever-growing interest due to their high atom-utilization efficiency and potential for cost-effective of hydrogen production. However, enhancing the hydrogen evolution reaction (HER) performance remains a key challenge in developing SACs for HER technology. Herein, we employed first-principles calculations in conjunction with the climbing-image nudged elastic band (CI-NEB) method to explore the effect of surface ligands (F, Cl, Br, I) on the HER performance and mechanism of single-atom (Pd or Cu)-anchored MoS2 monolayer. The results indicate that the relative Gibbs free energy for the adsorbed hydrogen atom in the I-Pd@MoS2 system is an exceptionally low value of -0.13 eV, which is not only comparable to that of Pt-based catalysts but also significantly more favorable than the calculated 0.84 eV for Pd@MoS2. However, the introduction of ligands to Cu@MoS2 deteriorates HER performance due to strong coupling between the absorbed H and ligands. It reveals that the ligand I restructures the local chemical microenvironment surrounding the SAC Pd, leading to impurity bands near the Fermi level that couple favorably with the s states of H atoms, yielding numerous highly active sites to enhance catalytic performance. Furthermore, the CI-NEB method elucidates that the enhanced HER mechanism for the I-Pd@MoS2 catalyst should belong to the coexistence of the Volmer-Tafel and Volmer-Heyrovsky reactions. This investigation provides a valuable framework for the experimental design and development of innovative single-atom catalysts.

We present a hydrodynamic theory of anisotropic and inversion-asymmetric moving active permeable fluid membranes. These are described by an anisotropic Kardar-Parisi-Zhang equation. Depending upon the anisotropy parameters, the membrane can be large-scale anisotropic and logarithmically rough with translational quasi long range order and orientational long range order, together with the relaxational dynamics being logarithmically faster than ordinary diffusion. For other choices of the anisotropy parameters, the membrane is either effectively isotropic and algebraically rough with translational short, but orientational long range order, or crumpled.

Extending the Schramm--Loewner Evolution (SLE) to model branching structures while preserving conformal invariance and other stochastic properties remains a formidable research challenge. Unlike simple paths, branching structures, or trees, must be associated with discontinuous driving functions. Moreover, the driving function of a particular tree is not unique and depends on the order in which the branches are explored during the SLE process. This study investigates trees formed by nontrapping invasion percolation (NTIP) within the SLE framework. Three strategies for exploring a tree are employed: the invasion percolation process itself, Depth--First Search (DFS), and Breadth--First Search (BFS). We analyze the distributions of displacements of the Loewner driving functions and compute their spectral densities. Additionally, we investigate the inverse problem of deriving new traces from the driving functions, achieving a reasonably accurate reconstruction of the tree-like structures using the BFS and NTIP methods. Our results suggest the lack of conformal invariance in the exploration paths of the trees, as evidenced by the non-Brownian nature of the driving functions for the BFS and NTIP methods, and the inconsistency of the diffusion constants for the DFS method.

We consider $L$-directional associative memories, composed of $L$ Hopfield networks, displaying imitative Hebbian intra-network interactions and anti-imitative Hebbian inter-network interactions, where couplings are built over a set of hidden binary patterns. We evaluate the model's performance in reconstructing the whole set of hidden binary patterns when provided with mixtures of noisy versions of these patterns. Our numerical results demonstrate the model's high effectiveness in the reconstruction task for structureless and structured datasets.

The intrinsic magnetic topological insulator (IMTI) family $[\mathrm{MnTe}][\mathrm{Bi}_{2}\mathrm{Te}_{3}]_{\mathrm{n}}$ has demonstrated magneto-topological properties dependent on $n$, making it a promising platform for advanced electronics and spintronics. However, due to technical barriers in sample synthesis, their properties in the large $n$ limit remain unknown. To overcome this, we utilized the atomic layer-by-layer molecular beam epitaxy (ALL-MBE) technique and achieved IMTIs with $n$ as large as 15, far beyond the previously reported in bulk crystals or thin films. Then, we discover that the "single-layer magnet (SLM)" phase, primarily determined by intralayer ferromagnetic coupling, emerges for $n >$ $\sim 4$ and remains little affected up to $n = 15$. Nonetheless, still, non-zero, interlayer ferromagnetic coupling is necessary to stabilize the SLM phase, suggesting that the SLM phase eventually disappears in the $n\to\infty$ limit. This study uncovers the secrets of IMTIs beyond the thermodynamic limit and opens a door to diverse magneto-topological applications.

Moir\'e superlattices created by stacking atomic layers of transition metal dichalcogenide semiconductors have emerged as a class of fascinating artificial photonic and electronic materials. An appealing attribute of these structures is the inheritance of the valley degree of freedom from the constituent monolayers. Recent studies show evidence that the valley polarization of the moir\'e excitons is highly tunable. In heterojunctions of WSe2/WS2, marked improvement in valley polarization is observed by increasing optical excitation power, a behavior that is quite distinct from the monolayers, and lacks a clear understanding so far. In this work, we show that this highly tunable valley property arises from filling of the moir\'e superlattice, which provides an intriguing mechanism for engineering these quantum opto-valleytronic platforms. Our data further demonstrate that the long-range electron-hole exchange interaction, despite being significantly weakened in the junctions, is the dominant source of moir\'e exciton intervalley scattering at low population. Using magnetic field tuning, we quantitatively determine the exchange interaction strength to be 0.03 meV and 0.24 meV for 0- and 60-degrees twisted samples respectively in our experiments, about one order of magnitude weaker than that in the monolayers.

Controlling the flow of heat in quantum systems or circuits is very desirable for the development of quantum technologies. Here, we investigate the quantum heat transport in a driven hybrid magnonphoton system in contact with two thermal baths operating at different temperatures. Specifically, we analyze the role of the parameters of the hybrid quantum system in the processes that lead to the asymmetry of the steady-state heat current. We find that the thermal rectification is high in the regime of weak magnon-photon hybridization strength and large magnon-drive. Moreover, this driving and the system parameters could serve as experimental knobs to tune the thermodynamic properties of the magnon-photon system, as we demonstrate for the rectification parameter tunable by the drive in its entire physical range. The results from this research would provide very useful insight into the design of quantum thermal machines with a driven magnon-photon system.

The contribution of flexoelectric coupling to the long-range order parameter fluctuations in ferroics can be critically important to the ferron dispersion and related polar, pyroelectric and electrocaloric properties. Here we calculate analytically the dispersion relations of soft optic and acoustic "flexo-phonons" and "flexo-ferrons" by incorporating the flexoelectric coupling, damping, and higher elastic gradients in the Landau-Ginzburg-Devonshire free energy functional using the van der Waals uniaxial ferrielectric CuInP2S6 as an example. We analyze the changes in the flexo-phonon and flexo-ferron spectra arising from the appearance of spatially modulated phases induced by the flexoelectric coupling. We show that the free energy landscape of CuInP2S6 determines the specific features of its phonon spectra and ferron dispersion. We also discuss the contributions of optic and acoustic flexo-ferrons to the pyroelectric and electrocaloric responses of CuInP2S6 at low temperatures.

Understanding how renormalized quasiparticles emerge in strongly correlated electron materials provides a challenge for both experiment and theory. It has been predicted that distinctive spin and orbital screening mechanisms drive this process in multiorbital materials with strong Coulomb and Hund's interactions. Here, we provide the experimental evidence of both mechanisms from angle-resolved photoemission spectroscopy on RbFe$_2$As$_2$. We observe that the emergence of low-energy Fe 3$d_{xy}$ quasiparticles below 90K is tied to spin screening. A second process changes the spectral weight at high energies up to room temperature. Supported by theoretical calculations we attribute it to orbital screening of Fe 3d atomic excitations. These two cascading screening processes drive the temperature evolution from a bad metal to a correlated Fermi liquid.

We present a percolation model that is inspired by recent works on immiscible two-phase flow in a mixed-wet porous medium made of a mixture of grains with two different wettability properties. The percolation model is constructed on a dual lattice where the sites on the primal lattice represent the grains of the porous medium, and the bonds on the dual lattice represent the pores in between the grains. The bonds on the dual lattice are occupied based on the two adjacent sites on the primal lattice, which represent the pores where the capillary forces average to zero. The spanning cluster of the bonds, therefore, represents the flow network through which the two immiscible fluids can flow without facing any capillary barrier. It turns out to be a percolation transition of the perimeters of a site percolation problem. We study the geometrical properties at the criticality of the perimeter system numerically. A scaling theory is developed for these properties, and their scaling relations with the respective density parameters are studied. We also verified their finite-size scaling relations. Though the site clusters and their perimeters look very different compared to ordinary percolation, the singular behaviour of the associated geometrical properties remains unchanged. The critical exponents are found to be those of the ordinary percolation.

Many combinatorial optimization problems fall into the non-polynomial time NP-hard complexity class, characterized by computational demands that increase exponentially with the size of the problem in the worst case. Solving large-scale combinatorial optimization problems efficiently requires novel hardware solutions beyond the conventional von Neumann architecture. We propose an approach for solving a type of NP-hard problem based on coupled oscillator networks implemented with charge-density-wave condensate devices. Our prototype hardware, based on the 1T polymorph of TaS2, reveals the switching between the charge-density-wave electron-phonon condensate phases, enabling room-temperature operation of the network. The oscillator operation relies on hysteresis in current-voltage characteristics and bistability triggered by applied electrical bias. This work presents a network of injection-locked, coupled oscillators whose phase dynamics follow the Kuramoto model and demonstrates that such coupled quantum oscillators naturally evolve to a ground state capable of solving combinatorial optimization problems. The coupled oscillators based on charge-density-wave condensate phases can efficiently solve NP-hard Max-Cut benchmark problems, offering advantages over other leading oscillator-based approaches. The nature of the transitions between the charge-density-wave phases, distinctively different from resistive switching, creates the potential for low-power operation and compatibility with conventional Si technology.

The study of topological band theory in classical structures has led to the development of novel topological metamaterials with intriguing properties. While single-gap topologies are well understood, recent novel multi-gap phases have garnished increasing interest. These novel phases are characterized by invariants, such as the Euler and second Stiefel-Whitney classes, which involve Bloch eigen-subspaces of multiple bands and can change by braiding in momentum space non-Abelian charged band degeneracies belonging to adjacent energy gaps. Here, we theoretically predict and experimentally demonstrate that two of such topological phases can coexist within a single system using vectorial elastic waves. The inherent coupling between different polarization modes enables non-Abelian braiding of nodal points of multiple energy band gaps and results in coexisting Euler and Stiefel-Whitney topological insulator phases. We furthermore unveil the central role played by the topologically stable Goldstone modes' degeneracy. Our findings represent the first realization of hybrid phases in vectorial fields exhibiting topologically nontrivial Goldstone modes, paving the way for bifunctional applications that leverage the coexistence of topological edge and corner states.

To analyze the $\pm J$ XY spin-glass in three dimensions, we verified a method aimed at obtaining a high-precision dynamical exponent $z$ from the correlation length in the nonequilibrium relaxation process. The obtained $z$ yielded consistent and highly accurate results in previous studies for relatively well-studied models -- specifically, the three-dimensional (3D) ferromagnetic Ising model and the 3D $\pm J$ Ising model. Building on these previous studies, we used this method and the dynamical scaling method to analyze the 3D $\pm J$ XY model and obtained highly precise critical temperatures and exponents. These findings support the spin chirality decoupling picture, explaining the experimental spin-glass phase transition.

The corrosion behavior of NiCr alloys in molten FLiNaK salt is governed by complex Cr-F chemical interactions, necessitating a fundamental understanding for enhancing alloy performance in harsh environments. However, significant gaps remain in our understanding of the dynamic atomic-scale processes driving the progression of molten salt corrosion. This study employs reactive force field-based molecular dynamics simulations to unravel the influence of crystallographic orientation, temperature, and external electric fields on corrosion kinetics. The (100), (110), and (111) orientations of Ni$\mathrm{_{0.75}}$Cr$\mathrm{_{0.25}}$ alloys are evaluated at temperatures from 600 to 800{\deg}C, with and without electric fields. Results reveal that Cr dissolution and near-surface diffusion drive pitting-like surface morphology evolution. The (110) surface shows the highest corrosion susceptibility, while the (100) and (111) surfaces exhibit greater resistance, with (111) being the most stable. The corrosion activation energy, derived from the Arrhenius relation, ranges from 0.27 eV to 0.41 eV, aligning well with limited experimental data yet significantly lower than bulk diffusion barriers. This finding indicates that corrosion progression is primarily a kinetically controlled near-surface process, rather than being limited by bulk diffusion as suggested in previous understanding. Additionally, electric fields perpendicular to the interface are found to asymmetrically modulate corrosion dynamics, where a positive field (+0.10 V/{\AA}) promotes Cr dissolution. In comparison, a negative field (-0.10 V/{\AA}) largely suppresses corrosion, which can be effectively used to mitigate corrosion. These findings, along with atomistic details into the corrosion mechanisms, offer strategic perspectives for designing corrosion-resistant materials in advanced high-temperature molten salt applications.

The discovery of hyperbolic lattice, a discretized regularization of non-Euclidean space with constant negative curvature, has provided an unprecedented platform to extend topological phases of matter from Euclidean to non-Euclidean spaces. To date, however, all previous hyperbolic topological states are limited to conventional type-I hyperbolic lattice with a single edge, leaving the dynamic transfer of hyperbolic topological states between different edges completely unresolved. Here, by extending the hyperbolic topological physics from the conventional type-I hyperbolic lattices to the newfangled type-II hyperbolic lattices, we report the type-II hyperbolic Chern insulator featuring outer and inner chiral edge states and demonstrate their dynamic transfer across the bulk to the opposite edge via two distinct mechanisms: anti-parity-time phase transition and Landau-Zener single-band pumping. Our work lays the foundation for further exploring the dynamic evolution of hyperbolic topological effects, with the final goal of inspiring applications leveraging dynamic manipulations of the hyperbolic topological states.

Enhancement and peaks in near-field radiative heat transfer (NFRHT) typically arise due to surface phonon-polaritons, plasmon-polaritons, and electromagnetic (EM) modes in structured materials. However, the role of material quantum coherence in enhancing near-field radiative heat transfer remains unexplored. Here, we unravel that NFRHT in superconductor-ferromagnetic systems displays a unique peak at the superconducting phase transition that originates from the quantum coherence of Bogoliubov quasiparticles in superconductors. Our theory takes into account evanescent EM radiation emanating from fluctuating currents comprising Cooper pairs and Bogoliubov quasiparticles in stark contrast to the current-current correlations induced by electrons in conventional materials. Our proposed NFRHT configuration exploits ferromagnetic resonance at frequencies deep inside the superconducting band gap to isolate this superconducting coherence peak. Furthermore, we reveal that Cooper pairs and Bogoliubov quasiparticles have opposite effects on near-field thermal radiation and isolate their effects on many-body radiative heat transfer near superconductors. Our proposed phenomenon can have applications for developing thermal isolators and heat sinks in superconducting circuits.

This study explores how molecular shape changes influence the phase behavior of liquid crystals, particularly the nematic (N) phase of 5CB, through all-atom molecular dynamics (MD) simulations. The results demonstrate that molecular shape anisotropy increases in the N phase, with molecules adopting more elongated conformations as aggregation occurs. We find that the shape distribution is temperature- and aggregation-dependent, and the molecular shape relaxation time is longer in the N phase compared to isolated molecules. Additionally, the study proposes a revision to Onsager and Maier-Saupe theories, considering molecular shape distribution changes, which could improve the explanation of the N-I phase transition in liquid crystals. These findings contribute to a better understanding of the molecular behavior in liquid crystalline phases.

We present a detailed analytical and numerical examination, on square and triangular lattices, of the non-reciprocal planar spin model introduced in Dadhichi et al., Phys. Rev. E 101, 052601 (2020). We show that in principle the effect of lattice anisotropy should persist at large scales, leading to a ''mass'' for the angle field of the spins, and behaviour not in the ''Malthusian Toner-Tu'' universality class. Numerically, however, we find power-law scaling of long-wavelength equal-time correlators in the polar-ordered phase of our lattice model. The mass, if present, is very small. Focussing on topological defects, we show numerically that defect interactions are highly anisotropic with respect to the mean ordering direction. In particular, the constituents of a $\pm 1$ pair are shielded from each other in a class of configurations, deferring their annihilation and allowing time for the nucleation of further defects. The result, we show numerically, is the destruction of the polarised phase via an aster apocalypse reminiscent of that found by Besse et al., Phys. Rev. Lett. 129, 268003 (2022), for the Malthusian Toner-Tu equation.

Skyrmions--topologically protected nanoscale spin textures with vortex-like configurations--hold transformative potential for ultra-dense data storage, spintronics and quantum computing. However, their practical utility is challenged by dynamic instability, complex interaction, and the lack of deterministic control. While recent efforts using classical wave systems have enabled skyrmion simulations via engineered excitations, these realizations rely on fragile interference patterns, precluding stable transport and flexible control. Here, we introduce a skyrmion molecule lattice, a novel architecture where pairs of spin skyrmions with opposite polarizability are symmetry-locked into stable molecule configurations. These molecules emerge as propagating eigenstates of the system, overcoming the static limitations of previous realizations. We further develop a boundary engineering technique, achieving precise control over skyrmion creation, deformation, annihilation, and polarizability inversion. As a proof of concept, we design a graphene-like acoustic surface wave metamaterial, where meta-atom pairs generate vortices with opposite orbital angular momenta, which couple to acoustic spin textures, forming skyrmion molecules. Experimental measurements confirm their stable transport and flexible control. Our work leverages the symmetry-locked molecule lattice to preserve the topological quasiparticle nature of skyrmions, offering a universal framework for their stabilization, transportation and manipulation. This bridges critical gaps in skyrmion physics, with potential impacts on wave-based sensing, information processing, and topological waveguiding.

Distilling the underlying principles from data has long propelled scientific breakthroughs. However, conventional data-driven machine learning -- lacking deep, contextual domain knowledge -- tend to yield opaque or over-complex models that are challenging to interpret and generalize. Here, we present LLM-Feynman, a framework that leverages the embedded expertise of large language models (LLMs) with systematic optimization to distill concise, interpretable formula from data and domain knowledge. Our framework seamlessly integrates automated feature engineering, LLM-based symbolic regression augmented by self-evaluation and iterative refinement, and formula interpretation via Monte Carlo tree search. Ablation studies show that incorporating domain knowledge and self-evaluation yields more accurate formula at equivalent formula complexity than conventional symbolic regression. Validation on datasets from Feynman physics lectures confirms that LLM-Feynman can rediscover over 90% real physical formulas. Moreover, when applied to four key materials science tasks -- from classifying the synthesizability of 2D and perovskite structures to predicting ionic conductivity in lithium solid-state electrolytes and GW bandgaps in 2D materials -- LLM-Feynman consistently yields interpretable formula with accuracy exceeding 90% and R2 values above 0.8. By transcending mere data fitting through the integration of deep domain knowledge, LLM-Feynman establishes a new paradigm for the automated discovery of generalizable scientific formula and theory across disciplines.

The technological world is in search of environmentally friendly methods of generating energy for the use of the ever growing needs of power for sustainable development of visually all facet of life. Solar energy form an environmentally friendly solution for the reduction of global warming. For usage in photovoltaic applications, this work explores the production and characterisation of nanostructured cobalt sulphide (CoS) doped with dysprosium (Dy), a rare earth element. In order to increase CoS's efficiency in solar energy conversion, rare earth doping is used to improve its optical, electrical, and structural characteristics. To maximize performance, precise Dy doping doses were used in the electrochemical synthesis of the nanomaterials. UV-visible spectroscopy were among the characterization methods used to examine the optical and structural characteristics of the doped CoS nanomaterials. Significant alterations in the bandgap and optical absorption behavior are shown by the results, indicating that Dy-Doped CoS nanostructures hold great promise for enhanced photovoltaic performance. This study opens the door for the use of Dy-doped CoS in renewable energy technologies by demonstrating their viability as prospective materials for next-generation solar cells.

This paper systematically investigates the thermodynamic properties of classical oscillators under different statistical distributions, focusing on the behavior of uniform distribution, two-level distribution, gamma distribution, log-normal distribution, and F-distribution as the nonequilibrium parameter q varies. By calculating Helmholtz free energy and entropy, we reveal the unique patterns and characteristics exhibited by each distribution during the process of moving away from equilibrium. The results show that uniform and two-level distributions exhibit consistent trends of decreasing free energy and increasing entropy under nonequilibrium statistics, reflecting an increase in system disorder. In contrast, the gamma, log-normal, and F-distributions display complex dual-equilibrium point phenomena, where the system can briefly return to equilibrium at specific q values. However, as q further increases, the system rapidly moves away from equilibrium, exhibiting pronounced nonequilibrium characteristics. These findings not only deepen our understanding of nonequilibrium statistical physics but also provide new theoretical perspectives and methods for studying the nonequilibrium behavior of complex systems.

In the context of a growing interdisciplinary interest in the angular momentum of wave fields, the spin-wave case has yet to be fully explored, with the extensively studied notion of spin transport being only part of the broader picture. Here we report experimental evidence for magnon orbital angular momentum, demonstrating that the mode exhibits rotation rather than remaining stationary. This conclusion is drawn from observations of the lifted degeneracy of waves with counter-rotating wave fronts. This requires an unambiguous formulation of spin and orbital angular momenta for spin waves, which we provide in full generality based on a systematic application of quantum field theory techniques. The results unequivocally establish magnetic dipole-dipole interactions as a magnetic-field controllable spin-orbit interaction for magnons. Our findings open a new research direction, leveraging the spectroscopic readability of angular momentum for azimuthal spin waves and other related systems.

In the context of an ever-expanding experimental and theoretical interest in the magnetization dynamics of mesoscopic magnetic structures, both in the classical and quantum regimes, we formulate a low energy field theory for the linear spin-waves in finite and textured ferromagnets and we perform its constrained canonical quantization. The introduction of a manifestly gauge invariant Lagrangian enables a straightforward application of the Noether's theorem. Taking advantage of this in the context of a broad class of axisymmetric ferromagnets of special conceptual and experimental relevance, a general expression of the conserved and quantized spin-wave total angular momentum is rigorously derived, while separate conservation and quantization of its orbital and spin components are established for a more restricted class of uniaxial exchange ferromagnets. Further particularizing this general framework to the case of axially saturated magnetic thin disks, we develop a semi-analytic theory of the low frequency part of the exchange-dipole azimuthal spin wave spectrum, providing a powerful theoretical platform for the analysis and interpretation of magnetic resonance experiments on magnetic microdots as further demonstrated in a joint paper [arxiv The Orbital Angular Momentum of Azimuthal Spin-Waves]

High-pressure studies reveal a stark contrast between the superconducting properties of double-layer Ruddlesden-Popper (RP) nickelates La$_2$PrNi$_2$O$_7$ and La$_3$Ni$_2$O$_7$. While La$_2$PrNi$_2$O$_7$ exhibits bulk superconductivity, La$_3$Ni$_2$O$_7$ displays filamentary behavior, suggesting that superconductivity is confined to phase interfaces rather than the bulk. Since magnetism emerges near the superconducting phase, understanding its differences in La$_3$Ni$_2$O$_7$ and La$_2$PrNi$_2$O$_7$ is essential for clarifying their underlying electronic and magnetic properties. In this work we study the magnetic responce of La$_2$PrNi$_2$O$_{6.96}$ under pressures up to 2.3 GPa using the muon-spin rotation/relaxation ($\mu$SR) technique. The application of external pressure increases the N\'{e}el temperature $T_{\rm N}$ from approximately 161 K at ambient pressure ($p=0$) to about 170 K at $p=2.3$ GPa. The temperature dependence of the internal magnetic field $B_{\rm int}(T)$ (i.e., the magnetic order parameter) follows the power-law relation $B_{\rm int} = B_{\rm int}(0) \left(1 - \left[T/T_{\rm N}\right]^\alpha \right)^\beta$, with consistent exponent values of $\alpha\simeq 1.95$ and $\beta\simeq 0.35$ across different pressures. The value of the ordered moments at the Ni sites, which is proportional to $B_{\rm int}$, remain unaffected by pressure. Our findings suggest that the magnetic properties of double-layer RP nickelate La$_3$Ni$_2$O$_7$ are broadly unaffected by Pr to La substitution.

Thermoelectric (Bi1-x Sbx)2Te3 (BST-x) compounds with x=0.2, 0.7 and 0.9 have been studied using synchrotron angle-dispersive powder x-ray diffraction in a diamond anvil cell up to 25 GPa (at room temperature). The results clearly indicate that all compounds of this study follow a similar structural evolution with the one of pure Bi2Te3 and Sb2Te3 under pressure. From the comparison between the critical pressures of the corresponding phase transitions, a clear trend of increasing critical pressure for the transition to the disordered solid-solution BCC phase was observed with the increase of Sb concentration. In the case of the BST-0.7, an extended stability of the solid-solution BCC phase up to, at least, 180 GPa was observed. Finally, electrical transport properties measurements under pressure for BST-0.7, document a reversible pressure-induced metallization above 12 GPa.

Odd-parity pairings offer a natural pathway for realizing topological superconductivity. When two identical even-parity superconductors form a $\pi$-junction, the metallic material sandwiched between them experiences an effective odd-parity pairing, facilitating the emergence of topological superconductivity in the intermediate region. In this work, we consider the intermediate material to be a two-dimensional spin-orbit-coupled Dirac semimetal. When the two superconductors are conventional s-wave superconductors, we find that a helical topological superconductor can be realized. This phase is characterized by the presence of a pair of helical Majorana edge states. Interestingly, when the superconductors are $s_{\pm}$-wave superconductors, we observe not only the helical topological superconductor but also an unconventional topological superconductor. The latter is distinguished by the existence of two pairs of helical Majorana edge states, despite the fact that the global topological invariants for this system take on trivial values. By further applying an in-plane magnetic field, we demonstrate that second-order topological superconducting phases can be achieved. These phases host isolated Majorana corner modes as well as twofold Majorana corner modes. Our findings reveal that two-dimensional $\pi$-junction Dirac semimetals can support a rich variety of topological superconducting phases, offering a versatile platform for exploring exotic topological phenomena.

We present the diagrammatic theory of the irreducible self-energy and Bethe-Salpeter kernel that naturally arises within the Green's function formalism for a general $N$-body non-hermitian interaction. In this work, we focus specifically on the coupled-cluster self-energy generated by the similarity transformation of the electronic structure Hamiltonian. We develop the biorthogonal quantum theory to construct dynamical correlation functions where the time-dependence of operators is governed by a non-hermitian Hamiltonian. We extend the Gell-Mann and Low theorem to include non-hermitian interactions and to generate perturbative expansions of many-body Green's functions. We introduce the single-particle coupled-cluster Green's function and derive the perturbative diagrammatic expansion for the non-hermitian coupled-cluster self-energy in terms of the `non-interacting' reference Green's function, $\tilde{\Sigma}[G_0]$. From the equation-of-motion of the single-particle coupled-cluster Green's function, we derive the self-consistent renormalized coupled-cluster self-energy, $\tilde{\Sigma}[\tilde{G}]$, and demonstrate its relationship to the perturbative expansion of the self-energy, $\tilde{\Sigma}[G_0]$. Subsequently, we show that the usual electronic self-energy can be recovered from the coupled-cluster self-energy by neglecting the effects of the similarity transformation. We show how the coupled-cluster ground state energy is related to the coupled-cluster self-energy and provide an overview of the relationship between approximations for the coupled-cluster self-energy, IP/EA-EOM-CCSD and the $G_0W_0$ approximation. As a result, we introduce the CC-$G_0W_0$ self-energy by leveraging the connections between Green's function and coupled-cluster theory. Finally, we derive the diagrammatic expansion of the coupled-cluster Bethe-Salpeter kernel.

We investigate the effects of temporal hyperuniformity of driving forces in the spherical model. The spherical model with $p$-body random interactions is a prototypical model to investigate the ergodicity breaking of glass transitions, where the spin-spin interactions are key ingredients to cause the ergodicity breaking. However, for the model driven by temporally hyperuniform noise, the strong anticorrelation of the noise can solely cause an ergodicity breaking even without spin-spin interactions. Near the transition point, the static susceptibility and relaxation time show power-law divergence with a common critical exponent, which varies depending on the strength of hyperuniformity.

A self-bound dipolar quantum droplet modulated by an shallow optical latticeare studied. It is found that the behaviors of the droplets in an optical lattice are similar with those without the optical lattice. In the shallow enough limit the properties of the periodically-modulated dipolar droplets are exactly the same with those without the optical lattice,which are self-bound for the absence of any trap in the polarization direction. So we conclude that the formation of droplets in an shallow optical lattice is the competition of atomici nteractions and the quantum fluctuations.The optical lattice can only modulate the droplets. Our model can also describe the finite-size dipolar droplet system.

We study two-dimensional superconductivity mediated by magnetic fluctuations at the interface between a ferromagnetic insulator and the nonsymmorphic topological crystalline insulator with a fourfold-degenerate Dirac point, wallpaper fermion. We demonstrate that BCS pairing with zero center-of-mass momentum induces chiral $p$-wave superconductivity, and the Amperean pairing with center-of-mass momentum $2k_{\rm F}$ can give rise to a parity-mixed superconducting state. We find that the Amperean pairing exhibits a mixture of $s$-wave and $p$-wave components due to the multiband nature of the wallpaper fermion and the easy-axis anisotropy of the ferromagnetic insulator. Additionally, we find that the stability of the superconducting state with BCS and the Amperean pairing is governed by the easy-axis anisotropy.

Ferroelastic materials (materials with switchable spontaneous strain) often are centrosymmetric, but their domain walls are always polar, as their internal strain gradients cause polarization via flexoelectricity. This polarization is generally not switchable by an external electric field, because reversing the domain wall polarity would require reversing the strain gradient, which in turn would require switching the spontaneous strain of the adjacent domains, destroying the domain wall in the process. However, domain wall polarization can also arise from biquadratic coupling between polar and non-polar order parameters (e.g. octahedral tilts in perovskites). Such coupling is independent of the sign of the polarization and thus allows switching between +P and -P. In this work, we seek to answer the question of whether the polarization of domain walls in ferroelastic perovskites is switchable, as per the symmetric biquadratic term, or non-switchable due to the unipolar flexoelectric bias. Using perovskite calcium titanate (CaTiO3) as a paradigm, molecular dynamics calculations indicate that high electric fields broaden the ferroelastic domain walls, thereby reducing flexoelectricity (as the domain wall strain gradient is inversely proportional to the wall width), eventually enabling switching. The polarization switching, however, is not ferroelectric-like with a simple hysteresis loop, but antiferroelectric-like with a double hysteresis loop. Ferroelastic domain walls thus behave as functional antiferroelectric elements, and also as nucleation points for a bulk phase transition to a polar state.

We obtain solutions for Eliashberg equations within the Nambu representation for a two-band model of iron-based superconductors with nonmagnetic impurities. Two cases of a transition between $s_{\pm}$ and $s_{++}$ states are considered: (i) the transition is accompanied by the abrupt change of the order parameter sign within one of the bands and (ii) the change is smooth. For both cases, we studied the role of a gauge defined by the coefficients preceding the Pauli matrices $\hat\tau_1$ and $\hat\tau_2$ in a self-energy expansion, which correspond to the components of the order parameter. We show that the absolute value of the order parameter is conserved for solutions in the clean and in the Born limits. In an intermediate case, between the Born and unitary limits, result depends on the solution for the clean limit. We show that a common gauge for the Eliashberg equations in which one of the order parameter components vanishes is essential for adequate description of the multiband superconducting systems.

Existing skyrmion nucleation methods lead to increased Joule heating, limiting the applicability to metallic Antiferromagnetic (AFM) systems. In this study, we propose a novel, energy-efficient mechanical method for nucleating AFM skyrmions using Surface Acoustic Waves (SAWs). SAWs, which propagate along material surfaces with minimal attenuation, generate dynamic strain that induces a spatially varying torque on magnetic spins, offering a viable alternative to traditional current-based methods. Using the Thiele approach we investigate skyrmion dynamics in special AFMs, NiO-like or CoO-like, incorporating a magnetoelastic term that accounts for the unique spin arrangements, where spins align oppositely within parallel planes. Our findings reveal that the deformation induced by SAWs, influenced by the magnetostriction of materials like NiO and CoO, can modify the spin configuration, consequently, alters the skyrmion dynamics. This study not only demonstrates the potential of SAWs for efficient skyrmion nucleation in AFMs but also introduces new theoretical insights into specific magnetoelastic-induced skyrmion dynamics in AFM systems.

Non-Abelian anyons such as Majorana zero modes (MZMs) have the potential to enable fault-tolerant quantum computing through topological protection. Experimentally reported InSb topological superconductor nanowires (TSNW) are investigated theoretically and numerically to evaluate their suitability to host MZMs. We employ eigenspectra analysis and quantum transport based on the non-equilibrium Green's function (NEGF) formalism to investigate the eigenenergies, Majorana wave functions via local density of states, transmission spectra for Andreev processes, and zero-bias conductance peaks (ZBCPs) in InSb TSNWs. For 1.6 {\mu}m- and 2.2 {\mu}m-long InSb TSNWs we demonstrate the existence of the optimum design space defined by the applied magnetic field and electrochemical potential, which leads to clear ZBCP signatures with a Majorana localization length down to ~340 nm.

The attractive Hubbard model plays a paradigmatic role in the study of superconductivity (superfluidity) and has become directly realizable in ultracold atom experiments on optical lattices. However, the critical temperatures, $T_c$'s, remain lower than the lowest temperatures currently achievable in experiments. Here, we explore a possible route to enhance $T_c$ by introducing an additional next-nearest-neighbor (NNN) hopping, $t^\prime$, in a two-dimensional square lattice. We perform sign-problem-free determinant quantum Monte Carlo simulations to compute response functions such as pairing correlation functions, superfluid density, and uniform spin susceptibility. Our results show that a judicious choice of $t^\prime$ can increase $Tc$ by up to $50\%$ compared to the case with only nearest-neighbor hopping. In contrast, the preformed pairs temperature scale, named pairing temperature, $T_p$, decreases with increasing $|t^{\prime}/t|$, which should represent a reduction of the pseudogap region, favoring a more BCS-like behavior at intermediate coupling. We further analyze the interacting density of states to characterize the transition from a pseudogap regime to a fully gapped superconducting state. These findings suggest that NNN hopping could be a viable route to increase $T_c$ to values closer to experimentally accessible temperature scales.

A phase transition can drive the spontaneous emergence of chiral orders in crystals below a critical temperature. However, selecting either a right- or a left-handed phase with the aid of electromagnetic fields is challenging, particularly when intrinsic polar and axial moments are lacking. In this work we show that \textit{purely} chiral phases with opposite handedness, when both deriving from one degenerate instability, are linked by accessible transition states. While these states compete with the chirality under an electromagnetic field, a circularly polarized source can select the handedness of the system. This selection is mediated by a chiral monopole and may further result in a hysteresis process of the gyrotropic properties, namely the optical activity, below the critical temperature. We suggest several materials, among which K$_3$NiO$_2$, as candidates for possible experimental observation.

The realization of various qubit systems based on high-quality hybrid superconducting quantum devices, is often achieved using semiconductor nanowires. For such hybrid devices, a good coupling between the superconductor and the conducting states in the semiconductor wire is crucial. GaAs/InAs core/shell nanowires with an insulating core, and a conductive InAs shell fulfill this requirement, since the electronic states are strongly confined near the surface. However, maintaining a good crystal quality in the conducting shell is a challenge for this type of nanowire. In this work, we present phase-pure zincblende GaAs/InAs core/shell nanowires and analyze their low-temperature magnetotransport properties. We observe pronounced magnetic flux quantum periodic oscillations, which can be attributed to a combination of Aharonov-Bohm and Altshuler-Aronov-Spivak oscillations. From the gate and temperature dependence of the conductance oscillations, as well as from supporting theoretical transport calculations, we conclude that the conducting states in the shell are in the quasi-ballistic transport regime, with few scattering centers, but nevertheless leading to an Altshuler-Aronov-Spivak correction that dominates at small magnetic field strengths. Our results demonstrate that phase-pure zincblende GaAs/InAs core/shell nanowires represent a very promising alternative semiconductor nanowire-based platform for hybrid quantum devices.

We investigate the effect of a magnetic field on the Kitaev model using the equation of motion approach for the spin Green's function. Our study considers both cases: suppressed magnetization and finite magnetization in the paramagnetic phase of the Kitaev model. When magnetization is suppressed, the specific heat exhibits an angular dependence with a $60^\circ$ periodicity, consistent with recent experimental observations in $\alpha$-RuCl$_3$. This behavior can be interpreted as a signature of Majorana fermion gap formation. However, when magnetization is included, the periodicity shifts from $60^\circ$ to $180^\circ$, suggesting that the Majorana fermion gap behavior is no longer present in this regime. Our results indicate that the suppression of magnetization is essential for observing features associated with Majorana fermions, suggesting that a nearest-neighbor antiferromagnetic interaction could contribute to this suppression.

Collective excitation of an interacting electron liquid called plasmon has distinct properties compared to those of a bare electron. Plasmons excited by a short voltage pulse and transmitted through quantum devices will distribute amongst electron conduction channels via Coulomb interactions, which is known as charge fractionalization. This process spreads plasmons into all Coulomb-coupled electron conduction channels, including those in neighbouring circuits, and makes it difficult to control them in quantum circuits. Here we demonstrate the isolation and on-demand selection of electron conduction channels contributing to the plasmon using a cavity, which enables us to control the velocity of propagating plasmons. We demonstrate an electron-channel blockade effect, where charge fractionalization to cavity-confined electron conduction channels is prohibited by the narrow energy distribution of the plasmon itself. This effect is unaffected by the energy fluctuation of the surrounding circuits. The electron-channel blockade offers a powerful tool for designing plasmonic circuits as it can be used to control the plasmon velocity by local parameters, suppress unwanted plasmonic excitation in nearby circuits, and select electron-channels of plasmon eigenstates in quantum interferometers.

Multipolar moments entail a new route to tackle frontier problems in superconductivity (SC). A key progress in the search for multipolar SC is the discovery of Pr$Tr_2$Al$_{20}$ ($Tr =$ Ti, V), which possesses quadrupolar and octupolar but no magnetic dipolar moments. The Kondo entanglement of these multipolar moments with conduction electrons leads to exotic SC within the multipolar ordered phase, though the precise nature of the SC remains unexplored. We experimentally investigate the SC gap structure of SC in PrTi$_{2}$Al$_{20}$ and its La-doping evolution. Our results indicate deviations from a single $s$-wave gap, instead favoring nodal $d$-wave or multiple gaps. While the SC is robust against La dilution, the SC gap structure changes with minimal La doping, coinciding with a sharp change in the ferroquadrupolar (FQ) order. This suggests an intimate link between the quadrupolar order parameter and SC pairing, providing insight into the coexistence of SC with multipolar order.

The thermal response of proximity Josephson junctions (JJs) is governed by the temperature ($T$)-dependent occupation of Andreev bound states (ABS), making them promising candidates for sensitive thermal detection. In this study, we systematically engineer ABS to enhance the thermal sensitivity of the critical current ($I_c$) of proximity JJs, quantified as $|\,dI_c/dT\,|$ for the threshold readout scheme and $|\,dI_c/dT \cdot I_c^{-1}\,|$ for the inductive readout scheme. Using a gate-tunable graphene-based JJ platform, we explore the impact of key parameters -- including channel length, transparency, carrier density, and superconducting material -- on the thermal response. Our results reveal that the proximity-induced superconducting gap plays a crucial role in optimizing thermal sensitivity. Notably, we see a maximum $|\,dI_c/dT \cdot I_c^{-1}\,|$ value of $0.6\,\mathrm{K}^{-1}$ at low temperatures with titanium-based graphene JJs. By demonstrating a systematic approach to engineering ABS in proximity JJs, this work establishes a versatile framework for optimizing thermal sensors and advancing the study of ABS-mediated transport.

We calculate the shift current response in twisted double bilayer graphenes (TDBG) by applying the perturbative approach to the effective continuum Hamiltonian. We have performed a systematic study of the shift current in AB-AB and AB-BA stacked TDBG, where we have investigated the dependence of the signal on the twist angle, the vertical bias voltage and the Fermi level. The numerical analyses demonstrate that a large signal is generated from the formation of the moir\'e minibands. Notably, we also found that there is a systematic sign reversal of the signal in the two stacking configurations below the charge neutrality point for large bias voltages. We qualitatively explain the origin of this sign reversal by studying the shift current response in AB-stacked bilayer graphene.

A low-energy neutral quasiparticle in a fractional quantum Hall system appears in the latter's energy spectrum on a sphere as a series of many-body excited states labeled by the angular momentum $L$ and whose energy is a smooth function of $L$ in the limit of large sphere radius. We argue that the signature of a nonvanishing spin (intrinsic angular momentum) $s$ of the quasiparticle is the absence, in this series, of states with total angular momentum less than $s$.We reinterpret the missing of certain states, observed in an exact-diagonalization calculation of the spectrum of the $\nu=7/3$ FQH state in a wide quantum well as well as in many proposed wave functions for the excited states as a consequence of the spin-2 nature of the zero-momentum magnetoroton.

Color centers exhibiting deep-level states within the wide bandgap h-BN monolayer possess substantial potential for quantum applications. Uncovering precise geometric characteristics at the atomic scale is crucial for understanding defect performance. In this study, first-principles calculations were performed on the most extensively investigated CBVN and NBVN color centers in h-BN, focusing on the out-of-plane displacement and their specific impacts on electronic, vibrational, and emission properties. We demonstrate the competition between the {\sigma}*-like antibonding state and the {\pi}-like bonding state, which determines the out-of-plane displacement. The overall effect of vibronic coupling on geometry is elucidated using a pseudo Jahn-Teller model. Local vibrational analysis reveals a series of distinct quasi-local phonon modes that could serve as fingerprints for experimental identification of specific point defects. The critical effects of out-of-plane displacement during the quantum emission process are carefully elucidated to answer the distinct observations in experiments, and these revelations are universal in quantum point defects in other layered materials.

Exceptional points (EPs) are prominent non-Hermitian band degeneracies that give rise to a variety of intriguing and unconventional phenomena. Similar to Weyl and Dirac points, EPs carry topological charges and comply with the celebrated fermion doubling theorems in lattices. Beyond these characteristics, EPs exhibit more exotic topological properties, particularly non-Abelian braiding topologies not seen in conventional degeneracies. Here, we investigate these foundational concepts of EPs in two-dimensional non-Hermitian lattices where the fundamental domain of the Brillouin zone is a Klein bottle, rather than a torus assumed in previous studies. We find that EPs do not necessarily appear in pairs with opposite topological charges in the Brillouin Klein bottle, thus violating the fermion doubling theorem. The violation occurs because, without crossing the boundary, the sum of the topological charges of EPs is in fact an even number rather than zero. Moreover, we uncover unique braiding topologies of EPs that cannot be captured by existing theories. Specifically, the composite braidings around all EPs equals the braiding along the boundary of the Brillouin Klein bottle. This novel braiding topology further confirms the failure of the fermion doubling theorem, and allows us to explore the non-Abelian braidings of EPs beyond the scope of topological charges. Our work highlights the fundamental role of Brillouin-zone topology in non-Hermitian systems.

Achieving atomically flat and stoichiometric films of chiral antiferromagnets (AFM) with two-dimensional kagome spin lattice structures are crucial for integrating these materials in both established and emerging antiferromagnetic spintronic devices. We report a systematic study of growth and anomalous Hall effect in (111)-oriented non-collinear AFM $Mn_{3+x}Pt_{1-x}$ films with varying compositions, for x = 0.09, 0.17, 0.28. Under optimized growth conditions, we obtain stoichiometric and atomically flat epitaxial $Mn_{3}Pt$(111) films on Si(100) substrate, as evidenced by X-ray reflectivity and scanning probe microscopy. The magnetization measurement showed that epitaxial strain can induce a magnetic phase transition from an incommensurate spin state ($T_2$) at x = 0.09 to a triangular all-in/all-out AFM spin order ($T_1$) at x = 0.17, 0.28. The change in magnetic ground state is evident in the transport characteristics, as the ($T_1$) state shows a robust intrinsic anomalous Hall effect (AHE) persisting till room temperature, in contrast to the ($T_2$) state where AHE is negligible. Our studies reveal a hole-dominated conductance with room temperature anomalous Hall conductivity (AHC) ranging from 5 to 16 $\Omega^{-1}cm^{-1}$ for x = 0.17 and 0.28 respectively. A scaling law is established, indicating that Hall resistivity is primarily governed by the intrinsic non-vanishing Berry curvature. The experimental observation corroborates the electronic structure calculations, which predicts the massless Dirac states near Fermi level in the bulk band structure, attributed to the presence of nonsymorphic glide symmetry. Additionally, we showed that chemical tuning via Mn doping can stabilize the required T$_1$ non-collinear AFM structure which enhance the topology driven intrinsic AHE.

The chiral loop-current (LC) phase in kagome metals AV3Sb5 (A = Cs, Rb, K) has attracted considerable attention as a novel quantum state driven by electron correlations. Scanning tunneling microscopy (STM) experiments have provided strong evidence for the chiral LC phase through the detection of chirality in the quasiparticle interference (QPI) signal. However, the fundamental relationship between ``QPI chirality'' and ``LC chirality'' remains unexplored. For instance, the QPI signal is unchanged even when all LC orders are inverted. Furthermore, only the chiral LC order cannot induce QPI chirality. At present, the true essence of kagome metals that we should learn from the remarkable QPI experiments remains elusive. To address this, we investigate the origin of the QPI signal in the LC phase using a large unit-cell tight-binding model for kagome metals. The LC phase gives rise to a $Z_3$ nematic phase, characterized by three distinct directors, under the Star-of-David bond order. Our findings demonstrate that the QPI chirality induced by a single impurity at site Z, denoted as $\chi_Z$, can take values of $\pm1$ (chiral) or 0 (achiral), depending on the direction of the $Z_3$ nematic order. Prominent QPI chirality originates from extremely dilute impurities ($\lesssim$0.1%) in the present mechanism. Notably, $\chi_Z$ ($=\pm1$, 0) changes smoothly with minimal free-energy barriers by applying a small magnetic field $B_z$, accompanied by a switching of the $Z_3$ nematic director. This study provides a comprehensive explanation for the observed ``$B_z$-switchable QPI chirality'' in regions with dilute impurities, offering fundamental insight into the chiral LC in kagome metals.

For the first time, a detailed analysis of the behaviour of the temperature dependences of the upper critical fields Hc2(T) has been carried out in the compounds (Dy1-xErx)Rh3.8Ru0.2B4 (x = 0, 0.2, 0.4). It is found that the Hc2(T) in (Dy0.8Er0.2)Rh3.8Ru0.2B4 has an inflection point at 3 kOe, which may be related to the low-temperature magnetic ordering, while a more exotic mechanism caused by the transition from ordinary singlet to triplet superconductivity is not excluded. For the first time, the experimental Hc2(T) dependences of (Dy1-xErx)Rh3.8Ru0.2B4 (x = 0, 0.2, 0.4) compounds have been fitted within the framework of Werthamer-Helfand-Hohenberg theory (WHH) with the Maki parameter alpha > 0, indicating that spin-paramagnetic effects due to magnetic exchange interactions play an essential role in suppressing superconductivity in these compounds.

In this work, we used 20 nm thick CdTe/SnTe/CdTe [001] quantum wells to make 6- and 8-terminal nano-structures with the etched cross-junctions of sub-micron width with walls directed along the [10], [01], and [11] surface crystallographic directions. We studied the low-temperature quantum magneto-transport to investigate the impact of lateral confinement on the states of topological carriers. Calculations showed that for narrow SnTe channels, almost flat bands with small energy dispersion are formed, and in the case of the [11] direction, the dispersionless states are strongly localized at the mesa edges. The measurements indicated that a current path associated with trivial states inside the quantum well was considerably narrowed due to disorder, leading to a significant reduction in channel conductivity. Such a high-resistance cross-junction has been used for measurements of non-linear transport in non-local configurations. The dependence of the differential resistance $R_\text{d}$ on the direct current $I_\text{DC}$ flowing through a selected pair of contacts was studied. For temperatures $T<1$ K, first an increase and then a decrease followed by a minimum of $R_\text{d}$ were observed. This is a characteristic $R_\text{d}(I_\text{DC})$ relationship that is often considered as the signature of the hydrodynamic flow of a fermionic liquid in narrow quantum channels, which in the case of SnTe can be formed by topological states located entirely at the inner edges of a planar cross-junction.

Inspired by recent predictions of superconductivity in B-C framework clathrates, we employ density functional theory to explore potential superconductors among hexagonal hydride-substituted compounds with compositions XB$_8$C, XB$_7$C$_2$, XB$_6$C$_3$, XB$_3$C$_6$, XB$_2$C$_7$, and XBC$_8$. Our high-throughput calculations on 96 compounds reveal several dynamically stable candidates exhibiting superconductivity at ambient pressure. Analysis of electronic structures and electron-phonon coupling demonstrates that CaB$_8$C, SrB$_8$C, and BaB$_8$C possess superconducting transition temperatures ($T_c$) exceeding 50 K, with CaB$_8$C exhibiting the highest predicted $T_c$ of 77.1 K among all stable compounds studied. These findings expand the family of B-C clathrate superconductors and provide valuable insights for experimental efforts aimed at discovering novel superconducting materials.

Amorphous multi-element materials offer unprecedented tunability in composition and properties, yet their rational design remains challenging due to the lack of predictive structure-property relationships and the vast configurational space. Traditional modeling struggles to capture the intricate short-range order that dictates their stability and functionality. We here introduce ApolloX, a pioneering predictive framework for amorphous multi-element materials, establishing a new paradigm by integrating physics-informed generative modeling with particle swarm optimization, using chemical short-range order as an explicit constraint. By systematically navigating the disordered energy landscape, ApolloX enables the targeted design of thermodynamically stable amorphous configurations. It accurately predicts atomic-scale arrangements, including composition-driven metal clustering and amorphization trends, which are well-validated by experiments, while also guiding synthesis by leveraging sluggish diffusion to control elemental distribution and disorder. The resulting structural evolution, governed by composition, directly impacts catalytic performance, leading to improved activity and stability with increasing amorphization. This predictive-experimental synergy transforms the discovery of amorphous materials, unlocking new frontiers in catalysis, energy storage, and functional disordered systems.

We revealed that with the measurement of the scattering phase shift of electron in low-dimensional or mesoscopic systems local objects of hierarchy of density of states can also determine experimentally. In recent times, it has been exhibited that in mesoscopic systems certain objects of density of states (DOS) hierarchy like local partial DOS, partial DOS, injectivity, emissivity, etc. can become negative in presence of Fano resonance. Negativity of local partial density of states can be interpreted as the losing coherent electrons in reverse time. This may have implications for the thermodynamic properties of these mesoscopic systems. In these negative local partial states, electrons may behave akin to positrons, resulting in practical the possibility of electron-electron interaction. The objective of this research is to reveal some manifestations of local objects in mesoscopic systems, employing rigorous calculations utilizing two different approaches: a continuum model and a discrete or tight binding model. It has been demonstrated that negative local partial states are correlated with Fano-resonance featuring a {\pi} phase drop.

Accurate computational predictions of metal-organic frameworks (MOFs) and their properties is crucial for discovering optimal compositions and applying them in relevant technological areas. This work benchmarks density functional theory (DFT) approaches, including semi-local, meta-GGA, and hybrid functionals with various dispersion corrections, on MOF-5 and three of its computationally predicted derivatives, analyzing structural, electronic, and vibrational properties. Our results underline the importance of explicitly treating van der Waals interactions for an accurate description of structural and vibrational properties, and indicate the meta-GGA functional R2SCAN as the best balance between accuracy and efficiency for characterizing the electronic structure of these systems, in view of future high-throughput screening studies on MOFs.

Polar domains and their manipulation-particularly the creation and dynamic control-have garnered significant attention, owing to their rich physics and promising applications in digital memory devices. In this work, using density functional theory (DFT) and deep learning molecular dynamics (DLMD) simulations, we demonstrate that polar domains can be created and manipulated in twisted bilayers of ferroelectric CuInP2S6, as a result of interfacial ferroelectric (antiferroelectric) coupling in AA (AB) stacked region. Unlike the topological polar vortex and skyrmions observed in superlattices of (PbTiO3)n/(SrTiO3)n and sliding bilayers of BN and MoS2, the underlying mechanism of polar domain formation in this system arises from stacking-dependent energy barriers for ferroelectric switching and variations in switching speeds under thermal perturbations. Notably, the thermal stability and polarization lifetimes are highly sensitive to twist angles and temperature, and can be further manipulated by external electric fields and strain. Through multi-scale simulations, our study provides a novel approach to exploring how twist angles influence domain evolution and underscores the potential for controlling local polarization in ferroelectric materials via rotational manipulation.

Using the example of a pressed sample consisting of chromium dioxide nanoparticles coated with insulating shells, we study the relationship between the electronic transport system and magnetic subsystem in granular spin-polarized metals. It is shown that the spin-polarized tunneling transport current can affect the coercivity fields of the percolation cluster formed in the sample with decreasing temperature.

Recent advances in experimental techniques and computational methods have significantly expanded the family of alkali antimonides, a class of semiconducting materials used as photocathodes in particle accelerators, unveiling new crystal structures and stoichiometries with improved stability and quantum efficiency. This work investigates the electronic and optical properties of eight Na- and K-based alkali antimonide binary crystals with 3:1 and 1:1 alkali-to-antimony ratios, which were predicted to be stable in a recent high-throughput screening study. Employing density functional theory and many-body perturbation theory, we find that all systems exhibit direct band gaps, except for monoclinic Na$_8$Sb$_8$, which has a nearly degenerate indirect gap. Optical spectra are characterized by near-infrared absorption onsets and intense visible excitations. Our analysis highlights the significant role of electron-hole correlations, particularly in K-based compounds, leading to exciton binding energies above 100~meV and sharper absorption peaks. An in-depth analysis of the electronic contributions to the excited states provides additional insight into the role of excitonic effects. By shedding light on the fundamental properties of alkali antimonide binary crystals, our results are relevant for the design and optimization of next-generation electron sources for particle accelerators.

Arabinoxylans are constituents of wheat flour that contribute to the dietary fiber properties of wheat. They exist in water-extractable and water-unextractable forms and contribute to human health. In bakery technology, especially the water-extractable arabinoxylans (WE-AX) are important due to their impact on viscosity and dough rheology. This study provides insights into the impact of wheat flour fermentation on WE-AX during sourdough production, offering potential applications for improving sourdough bread quality and its health benefits. The production of sourdoughs is known to increase the WE-AX fraction, yet the underlying (bio)chemical mechanisms remain unclear. This study investigated the alteration of WE-AX during the fermentation of wheat flour for sourdough production using 1H Diffusion Ordered SpectroscopY (DOSY) Nuclear Magnetic Resonance (NMR) at elevated temperature to analyze the structural changes of WE-AX during wheat flour fermentation for sourdough production with different lactic acid bacteria (LAB) strains. The results confirmed that DOSY NMR at elevated temperatures greatly improved the applicability of the method for analyzing larger biomolecules. Overall, a size reduction of the WE-AX compounds with increasing fermentation time was found. This was indicated both by the occurrence of higher self-diffusion coefficients, and increased transverse relaxation times. Further research is necessary to explain deviations from the general trend.

Motivated by the paradigm of a super-Maltusian population catastrophe, we study a simple stochastic population model which exhibits a finite-time blowup of the population size and is strongly affected by intrinsic noise. We focus on the fluctuations of the blowup time $T$ in the asexual binary reproduction model $2A \to 3A$, where two identical individuals give birth to a third one. We determine exactly the average blowup time as well as the probability distribution $\mathcal{P}(T)$ of the blowup time and its moments. In particular, we show that the long-time tail $\mathcal{P}(T\to \infty)$ is purely exponential. The short-time tail $\mathcal{P}(T\to 0)$ exhibits an essential singularity at $T=0$, and it is dominated by a single (the most likely) population trajectory which we determine analytically.

Introducing topologically protected skyrmions in graphene holds significant importance for developing high-speed, low-energy spintronic devices. Here, we present a centrosymmetric ferromagnetic graphene/trilayer Cr2Ge2Te6/graphene heterostructure, demonstrating the anomalous and topological Hall effect due to the magnetic proximity effect. Through gate voltage control, we effectively tune the emergence and size of skyrmions. Micromagnetic simulations reveal the formation of skyrmions and antiskyrmions, which respond differently to external magnetic fields, leading to oscillations in the topological Hall signal. Our findings provide a novel pathway for the formation and manipulation of skyrmions in centrosymmetric two-dimensional magnetic systems, offering significant insights for developing topological spintronics.

Sum frequency generation (SFG) and difference frequency generation (DFG) are second order nonlinear processes where two lasers with frequencies $\omega_1$ and $\omega_2$ combine to produce a response at frequency $\omega = \omega_1 \pm \omega_2$ . Compared with other nonlinear responses such as second-harmonic generation, SFG and DFG allow for tunability over a larger range. Moreover, the optical response can be enhanced by selecting the two laser frequencies in order to match specific electron-hole transitions. Here, we propose a first-principles framework based on the real-time solution of an effective Schr\"odinger equation to calculate the SFG and DFG in various systems, such as bulk materials, 2D materials, and molecules. Within this framework, one can select from various levels of theory for the effective one-particle Hamiltonian to account for local-field effects and electron-hole interactions. To assess the approach, we calculate the SFG and DFG of two-dimensional crystals, h-BN and MoS$_2$ monolayers, both within the independent-particle picture and including many-body effects. Additionally, we demonstrate that our approach can also extract higher-order response functions, such as field-induced second-harmonic generation. We provide an example using bilayer h-BN.

Fermi arcs are one of the characteristic features of Weyl semimetals, appearing as surface states that connect Weyl points with opposite chiralities. It has also been suggested that Fermi arcs can emerge in the bulk due to the interplay between magnetic textures and Weyl physics. We focus on Ti$_2$MnAl which is an ideal magnetic Weyl semimetal with a compensated ferrimagnetic order. We systematically analyze domain wall-induced Fermi arcs in Ti$_2$MnAl using an effective tight-binding model. By varying the strength of spin-orbit coupling, we confirmed that these domain wall-induced Fermi arcs emerge as a result of shifts in the positions of the Weyl points. Furthermore, we found that these domain wall-induced Fermi arcs in Ti$_2$MnAl originate from the Chern number and represent a topologically robust state that is independent of the domain wall width.

In finite-size scaling analyses of critical phenomena, proper consideration of correction terms, which can come from different sources, plays an important role. For the Fortuin-Kasteleyn representation of the $Q$-state Potts model in two dimensions, although the subleading magnetic scaling field, with exactly known exponent, is theoretically expected to give rise in finite-size-scaling analyses, numerical observation remains elusive probably due to the mixing of various corrections. We simulate the O($n$) loop model on the hexagonal lattice, which is in the same universality class as the $Q=n^2$ Potts model but has suppressed corrections from other sources, and provides strong numerical evidence for the attribution of the subleading magnetic field in finite-size corrections. Interestingly, it is also observed that the corrections in small- and large-cluster-size regions have opposite magnitudes, and, for the special $n=2$ case, they compensate with each other in observables like the second moment of the cluster-size distribution. Our finding reveals that the effect of the subleading magnetic field should be taken into account in finite-size-scaling analyses, which was unfortunately ignored in many previous studies.

We report the first quantitative study of the onset of dawn choruses of cicadas in several natural habitats. A time-frequency analysis of the acoustical signals is used to define an order parameter for the development of collective singing. The ensemble of recordings reveals that the chorus onset times accurately track the changing sunrise times over the course of many weeks, occurring within civil twilight at a solar elevation of -$3.8^\circ \pm 0.2^\circ$. Despite day-to-day variations in the amplitude of fully developed choruses, the order parameter data collapse to a common sigmoidal curve when scaled by those amplitudes and shifted by the onset time, revealing a characteristic rise time of ~60 s for a chorus to reach saturation amplitude. The results are used to obtain the cumulative distribution function of singing as a function of ground illumination, from which is obtained a generalized susceptibility which exhibits a narrow peak with a half-width of $\sim\! 12\%$. The variance of the order parameter exhibits a similar peak, suggesting that a generalized fluctuation-dissipation theorem holds for this system. A model of decision-making under ramps of a control parameter is developed and can achieve a quantitative match to the data. It suggest that sharpness of the susceptibility peak reflects cooperative decision-making arising from acoustic communication.

We consider one-dimensional, integrable many-body classical and quantum systems in thermal equilibrium. In the classical case, we use the classical limit of the Bethe equations to obtain a self-consistent integral equation whose solution gives the distribution of asymptotic Bethe momenta, or rapidities, as well as the classical partition function in the canonical ensemble, and the thermal energy dispersion. For quantum gases, we obtain a similar integral equation, albeit in the grand canonical ensemble, with completely analogous results. We apply our theory to the classical and quantum Tonks and Calogero-Sutherland models, and our results are in perfect agreement with standard calculations using Yang-Yang thermodynamics. Remarkably, we show in a straightforward manner that the thermodynamics of the quantum Calogero-Sutherland model is in one-to-one correspondence with the ideal Fermi gas upon simple rescalings of chemical potential and density.

We study the high power ferromagnetic resonance (FMR) of perpendicularly magnetized BiYIG nanodisks where the uniaxial anisotropy almost compensates the shape anisotropy. We observe a strong saturation of the averaged magnetization upon moderately increasing the amplitude of the rf field and a broadening of the FMR line towards lower and higher magnetic field. Full micromagnetic simulations reveal that a self-modulation of the dynamic magnetization is responsible of this behavior. To get more insight into this unstable dynamics, it is analysed in terms of normal modes. The number of modes involved is found to rapidly increase above the critical threshold. Still, a normal modes model taking into account only a few of them and their mutual nonlinear couplings allows us to qualitatively reproduce the observed phenomenon. The normal modes analysis and micromagnetic simulations also predict a Suhl-like instability at larger excitation power when it is slowly increased from low values, and bistability. Using two-tone spectroscopy, we directly measure the self-modulation spectrum and provide experimental evidence of bistable dynamics. These findings open some perspectives of using high dimensional dynamics in magnetic nanostructures for unconventional information processing.

The movement of magnetic flux quanta (Abrikosov vortices) in superconductors leads to dissipation and is influenced by various ordering effects arising from vortex-vortex, vortex-defect, and vortex-edge interactions. Under combined dc and ac stimuli, when the distance traveled by fluxons during an ac cycle corresponds to an integer multiple of the vortex lattice period, the superconductor's current-voltage (I-V) curve displays synchronization (Shapiro) steps. However, in planar constrictions, frequency-locking effects rely on a perfectly ordered vortex lattice and are typically observed when periodic vortex pinning arrays dominate over intrinsic uncorrelated disorder. Here, we propose 3D superconducting open nanotubes as systems free of periodic disorder, where the I-V curves are expected to display pronounced Shapiro steps. Using the time-dependent Ginzburg-Landau equation, we attribute the predicted effect to a reduction in the dimensionality of vortex motion. Namely, rolling a planar film into a tube causes the 2D vortex array, which initially moves throughout the film, to evolve into quasi-1D vortex chains that are restricted to areas where the normal component of the magnetic field is near its maximum. The discussed effects are relevant for superconducting devices, where vortex nucleation frequency and voltage stabilization by an external ac stimulus can enhance their operation.

Recent magnetotransport studies on uniaxial ferromagnets have reported a cusp-like feature in Hall resistivity when the magnetic field is tilted away from the conventional orthogonal direction of the Hall measurement. This feature has often been attributed to the topological Hall effect arising from a non-coplanar spin structure. In this Letter, we have studied the uniaxial ferromagnet SmMn$_2$Ge$_2$ to demonstrate that this feature is rather a consequence of the non-orthogonal geometry of the Hall measurement and is expected to appear whenever the magnetic field is applied away from the easy axis of magnetization, non-orthogonal to the sample plane. The Hall resistivity, exhibiting this feature, scales with the orthogonal component of the magnetization, indicating that the observed feature is simply a manifestation of the anomalous Hall effect. We explain the origin of this feature based on the evolution of ferromagnetic domains under a non-orthogonal external magnetic field.

We present terahertz spectroscopic measurements of quantum spin dynamics in the honeycomb magnet K$_2$Co$_2$TeO$_6$ as a function of temperature, polarization and in an external magnetic field applied in the honeycomb plane. Magnetic excitations are resolved below the magnetic ordering temperature of $T_\text{N}$ = 12 K. In the applied magnetic field, we reveal characteristic field dependence not only for the magnetic excitations observed at zero field, but also a rich set of modes emerging in finite fields. The observed magnetic excitations exhibit clear dependence on the terahertz polarization, and characteristic features at field-induced phase transitions consistent with our high-field magnetization data. We cannot evidently resolve a continuumlike feature, even when the long-range magnetic order is presumably suppressed in the strong magnetic field, indicating that a Kitaev-type interaction, if existing, is subleading in this compound.

Due to their unique dimensionality, the physical properties of two-dimensional materials are deeply impacted by their surroundings, calling for a thorough understanding and control of these effects. We investigated the influence of the substrate and the pressure transmitting medium on bilayer graphene in a unique high-pressure environment where the sample is partially suspended and partially supported. By employing Raman spectroscopy with a sub-micron spatial resolution, we explored the evolution of strain and doping, and demonstrated that they are both similarly induced in the suspended and supported regions of the bilayer graphene within the studied pressure range. Almost full strain and doping transfer between the supported and suspended regions is concluded. We observed that charge carrier density saturates quickly at low pressures (2 GPa) while biaxial strain continuously increases with pressure. Additionally, Raman spatial mapping highlights a rather uniform doping and strain distribution, yet with significant local variations revealing a more complex scenario than previously documented by single-point studies at high pressure.

We study the dynamical consequences of combining the non-Hermitian skin effect with topological edge states. Focusing on the paradigmatic dissipative Hofstadter model, we find that the time-dependent particle density exhibits both chiral damping (due to the non-Hermitian skin effect) and edge-selective extremal damping (rooted in persistent topological edge states). We find that the time scales of chiral damping and edge-selective extremal damping decouple due to boundary-induced spectral topology, thus allowing observation of both effects under dynamics. We identify intermediate magnetic fields as the most favorable regime, since chiral damping is then partially recovered. More generally, our work sheds light on how open quantum systems are impacted by the combined presence of spectral and band topologies, and how their interplay can be probed directly.

Active particles are non-equilibrium entities that uptake energy and convert it into self-propulsion. A dynamically rich class of active particles having features of wave-particle coupling and memory are walking/superwalking droplets. Such classical, active wave-particle entities (WPEs) have been shown to exhibit hydrodynamic analogs of many single-particle quantum systems. We numerically investigate the dynamics of several WPEs and find that they self-organize into a bound cluster, akin to a nucleus. This active cluster exhibits various modes of collective excitations as the memory of the system is increased. Dynamically distinct excitation modes create a common time-averaged collective potential indicating an analogy with the bag model of a nucleus. At high memory, the active cluster can destabilize and eject WPEs whose decay statistics follow exponential laws analogous to radioactive nuclear decay. Hydrodynamic nuclear analogs open up new directions to pursue, both experimentally and numerically, within the nascent field of hydrodynamic quantum analogs.

Metallic antiferromagnets are essential for efficient spintronic applications due to their fast switching and high mobility, yet room-temperature metallic antiferromagnets are rare. Here, we investigate YbMn$_2$Ge$_2$, a room temperature antiferromagnet, and establish it as an exfoliable layered metal with altermagnetic surface states. Using multi-orbital Hubbard model calculations, we reveal that its robust metallic AFM ordering is stabilized by electronic correlations and a partially nested Fermi surface. Furthermore, we show that YbMn$_2$Ge$_2$ hosts symmetry-protected topological Dirac crossings, connecting unique even-order spin-polarized surface states with parabolic and inverted Mexican-hat-like dispersion. Our findings position YbMn$_2$Ge$_2$ as a promising platform for exploring the interplay of correlation, topology, and surface altermagnetism of layered antiferromagnets.

By measuring scanning tunneling spectroscopy on some large Bi islands deposited on FeTe$_{0.55}$Se$_{0.45}$ superconductors, we observe clear evidence of topological in-gap edge states with double peaks at about $\pm 1.0$ meV on the spectra measured near the perimeter of the islands. The edge states spread towards the inner side of the islands over a width of 2-3 nm. The two edge-state peaks at positive and negative energies both move to higher values with increase of the magnetic field, and they disappear near the transition temperature $T_\mathrm{c}$ of FeTe$_{0.55}$Se$_{0.45}$. The edge states are interpreted as the counter-propagating topological edge states induced by the strong spin-orbit coupling effect of the Bi island, and the zero-energy mode emerges when the edge states touch each other in some small Bi islands. Meanwhile, enhanced superconducting gaps are observed in the central regions of these Bi islands, which may be induced by the enhanced pair potential of the topological surface state. Our observations provide useful message for the nontrivial topological superconductivity on specific Bi islands grown on FeTe$_{0.55}$Se$_{0.45}$ substrate.

The propagation of a 3D crack in an heterogeneous material is studied using a phase field model. It is shown that in the case of randomly distributed inclusions of soft material in a matrix, the nature of the distribution has little effect on the effective elastic properties. On the opposite it affects significantly crack propagation. The less uniform distribution leads to higher thresholds for crack propagation.

The growth of cracks combines materials science, fracture mechanics, and statistical physics. The importance of fluctuations in the crack velocity is fundamental since it signals that the crack overcomes local barriers such as tough spots by avalanches. In ductile materials the omnipresent plasticity close to the crack tip influences the growth by history effects, which we here study in polymethylmetacrylate by various fatigue and creep protocols. We show how the crack tip local history may be encompassed in a time- and protocol dependent lengthscale, that allows to apply a statistical fracture description to the time-dependent crack growth rate, resolving the well-known paradox why fatigue cracks grow faster if the stress during a cycle is let to relax more from the peak value. The results open up novel directions for understanding fracture by statistical physics.

This study uses the density functional theory (DFT) approach with GGA-PBE to assess the effect of substituting alkali metals in Rb$_{2}$CaH and Cs-doped Rb$_{2}$CaH$_{4}$ on their hydrogen storage potential. To address the challenges associated with predicting accurate electronic properties in materials containing heavier elements such as cesium, spin-orbit coupling (SOC) effects have been incorporated into our calculations. The mechanical robustness of both Rb$_{2}$CaH$_{4}$ and Cs-doped Rb$_{2}$CaH$_{4}$, as demonstrated by their mechanical properties, highlights these materials as promising candidates due to their stability in hydrogen storage applications. Anisotropic factors show that all materials exhibit anisotropy, suggesting a directional dependency in their properties. The Pugh ratio indicates that Rb$_{2}$CaH$_{4}$ and Cs-doped Rb$_{2}$CaH$_{4}$ are brittle materials. Based on the calculated band gap, the electronic band structure analysis, conducted using both HSE06 and GGA-PBE, shows that Rb$_{2}$CaH$_{4}$ and Cs-doped Rb$_{2}$CaH$_{4}$ are wide-bandgap materials. Rb$_{2}$CaH$_{4}$ and Cs-doped Rb$_{2}$CaH$_{4}$ exhibit the highest optical conductivity, absorption coefficient, and energy loss function among optoelectronic materials, emphasizing their superior absorption and electron transfer capabilities. The hydrogen storage capacity has been evaluated for practical applications; Rb$_{2}$CaH$_{4}$ and Cs-doped Rb$_{2}$CaH$_{4}$ show the highest gravimetric and volumetric capacities.

Proton-conducting solid oxide fuel cells (PC-SOFCs) are pivotal for their high proton conductivity and superior performance. The proton conduction mechanism is commonly described by the Grotthuss mechanism, involving proton rotation and transfer. While proton transfer is often considered the rate-limiting step, the underlying reasons remain unclear. Through density functional theory calculations on undoped, A-site doped, and B-site doped BaHfO$_3$ systems, we demonstrate that the rate-limiting nature of proton transfer stems from the formation of weaker hydrogen bonds. In systems with strong hydrogen bonds, proton rotation becomes non-negligible. We identify a critical hydrogen bond length that distinguishes strong from weak bonds, with shorter lengths correlating with distorted perovskite structures and configurations deviating from cubic. This insight into the necessity of rotation is crucial for screening and optimizing materials with superior proton conduction properties.

We present the fabrication process of bright $GaAs$ quantum dot (QD) photon sources by non-deterministic embedding into broadband monolithic $Al_{0.15}Ga_{0.85}As$ microlens arrays on gold-coated substrates. Arrays of cylindrical photoresist templates, with diameters ranging from $2$ $\mu m$ to $5$ $\mu m$, are thermally reflowed and subsequently transferred into the $Al_{0.15}Ga_{0.85}As$ thin-film semiconductor heterostructure with embedded quantum dots through an optimized anisotropic and three-dimensional shape-preserving reactive ion etching process. This methodology facilitated the fabrication of large-scale ($2$ $mm$ $\times$ $4$ $mm$) and densely packed arrays of uniformly shaped microlenses ($\sim$ $40 \times 10^3$ $mm^{-1}$), with the brightest emissions from QDs embedded in microlenses exhibiting lateral diameters and heights of $2.7$ $\mu m$ and $1.35$ $\mu m$, respectively. Finite-difference time-domain simulations of both idealized and fabricated lens shapes provide a comprehensive three-dimensional analysis of the device performance and optimization potentials such as anti-reflection coatings. It is found that free-space extraction (fiber-coupled) efficiencies of up to $62$ $\%$ ($37$ $\%$) are achievable for hemispherical QD-microlenses on gold-coated substrates. A statistical model for the fabrication yield of QD-microlenses is developed and experimentally corroborated by photoluminescence spectroscopy of fabricated microlens arrays. This analysis exhibited a free-space intensity enhancement by factors of up to $\times 200$ in approximately $1$ out of $200$ microlenses, showing good agreement to the theoretical expectations. This scalable fabrication strategy underscores the potential of these compact, high-efficiency sources offering new prospects for applications of these devices in future large-scale quantum networks.

The intentional growth of metastable surface structures of organic molecules adsorbed on inorganic substrates is a challenging task. It is usually unclear which kinetic mechanism leads to the metastable surface polymorph after a deposition experiment. In this work we investigate a growth procedure that allows to intentionally grow a defined metastable surface structure starting from thermodynamic equilibrium. This procedure is applicable to organic-inorganic interface systems that exhibit a thermodynamically stable connector structure that can be exploited to grow the metastable target structure. With specific temperature and pressure changes in the system a significant yield of the target polymorph can be achieved. We demonstrate this procedure on a simplified microscopic interface system of rectangular molecules adsorbing on a square lattice substrate with kinetic Monte Carlo growth simulations.

Material systems with lone-pair electrons have long been a treasure trove in the search for large second harmonic generation effects. Revealing the origin of second harmonic generation in nonlinear optical materials can provide theoretical guidance for the design of new materials. In this work, the origin of second harmonic generation in non-centrosymmetric materials containing lone pair electrons is revealed by analyzing the orbital interactions on the sublattice. Stereochemically inactive Pb 6s orbitals with high symmetry in CsPbCO3F contribute less to the second harmonic generation. In contrast, the contribution of stereochemically active Pb 6s orbital in PbB5O7F3 and PbB2O3F2 is more obvious. Significantly, the orbitals of the interaction between lead and oxygen make a very significant contribution because these orbitals are located at the band edge and in non-centrosymmetric sublattices.

We develop a machine-learned interatomic potential for AlCrCuFeNi high-entropy alloys (HEA) using a diverse set of structures from density functional theory calculated including magnetic effects. The potential is based on the computationally efficient tabulated version of the Gaussian approximation potential method (tabGAP) and is a general-purpose model for molecular dynamics simulation of the HEA system, with additional emphasis on radiation damage effects. We use the potential to study key properties of AlCrCuFeNi HEAs at different compositions, focusing on the FCC/BCC phase stability. Monte Carlo swapping simulations are performed to understand the stability and segregation of the HEA and reveal clear FeCr and Cu segregation. Close to equiatomic composition, a transition from FCC to BCC is detected, following the valence electron concentration stability rule. Furthermore, we perform overlapping cascade simulations to investigate radiation damage production and tolerance. Different alloy compositions show significant differences in defect concentrations, and all alloy compositions show enrichment of some elements in or around defects. We find that, generally, a lower Al content corresponds to lower defect concentrations during irradiation. Furthermore, clear short-range ordering is observed as a consequence of continued irradiation.

The evaporation dynamics of sessile drops are crucial for material deposition in applications like inkjet printing and pharmaceutical development. However, the evaporation behavior of high molecular weight polymer solutions and their impact on deposit morphology and flow fields are not well understood. This study investigates the evaporation dynamics and deposit morphology of polyethylene glycol (PEG) solution drops on hydrophobic substrates, with molecular weights ranging from 200 to 1000k g/mol, covering five orders of magnitude. The results show that vapor diffusion dominates the evaporation process across all PEG molecular weights. Using image analysis and micro-particle image velocimetry ($\mu$-PIV), we reveal that molecular weight affects contact line dynamics and internal flow, leading to diverse deposit morphologies, including spherical caps, pillars, pool-shaped disks, and flat disks. Transient divergence and P\'eclet number calculations further confirm the role of hydrodynamics in deposit formation. These findings provide insights into the hydrodynamic and thermodynamic factors governing evaporation in polymeric sessile drops, with implications for material fabrication and the development of inkjet printing and coating techniques.

Materials informatics (MI), which emerges from the integration of materials science and data science, is expected to greatly streamline the material discovery and development. The data used for MI are obtained from both computational and experimental studies, while their integration remains challenging. In our previous study, we reported the integration of these datasets by applying a machine learning model that captures trends hidden in the experimental datasets to compositional data stored in the computational database. In this study, we use the obtained data to construct materials maps, which visualize the relation in the structural features of materials, aiming to support study by the experimental researchers. The map is constructed using the MatDeepLearn (MDL) framework, which implements the graph-based representation of material structures, deep learning, and dimensional reduction for the map construction. We evaluate the obtained materials maps through statistical analysis and found that the MDL using message passing neural network (MPNN) enables efficient extraction of features that reflect the structural complexity of materials. Moreover, we found that this advantage does not necessarily translate into improved accuracy in predicting material properties. We attribute this unexpected outcome to the high learning performance inherent in MPNN, which can contribute to the structuring of data points within the materials map.

Electron charging play key roles in physiochemical processes, whose intrinsic stabilization in single molecules is desirable for tailoring molecular functionality and developing molecular devices, but remains elusive on surfaces. Here, we show molecular charge states can be self-stabilized via intramolecular distortion in single bis(phthalocyaninato)terbium(III) (TbPc2) double-decker molecules, that were grown on Pb(111) substrate. Using scanning tunneling microscopy and spectroscopy, we identify fractions of TbPc2 molecules reduce to 2-fold symmetry, expressing energy-split molecular orbitals and two types of different spin states. Our first principles calculations unveil that the symmetry reduction is induced by charging-triggered Jahn-Teller distortions, which lifts the degenerate orbitals into two 2-fold symmetric orbitals. Single or double occupancy of the lower-energy orbital results in different molecular spin states. Such intramolecular distortion traps the excess electrons stably without explicit involvement of the substrate, in contrast to previously observed molecular charge states. These charged single molecule can be manipulated with the tip individually. This study offers a new avenue for tailoring the charge and spin states of molecules.

Bioelectrochemistry is crucial for understanding biological functions and driving applications in synthetic biology, healthcare, and catalysis. However, current simulation methods fail to capture both the stochastic nature of molecular motion and electron transfer across the relevant picosecond-to-minute timescales. We present QBIOL, a web-accessible software that integrates molecular dynamics, applied mathematics, GPU programming, and quantum charge transport to address this challenge. QBIOL enables quantitative stochastic electron transfer simulations and has the potential to reproduce numerically any (bio) electrochemical experiments. We illustrate this potential by comparing our simulations with experimental data on the current generated by electrode-attached redox-labeled DNA, or by nanoconfined redox species, in response to a variety of electrical excitation waveforms, configurations of interest in biosensing and catalysis. The adaptable architecture of QBIOL extends to the development of devices for quantum and molecular technologies, positioning our software as a powerful tool for enabling new research in this rapidly evolving field.

The remarkable material DIO presents fascinating behaviors. It has been extensively studied as one of the first materials exhibiting a ferroelectric nematic phase. However, at higher temperatures it exhibits what has been termed the Smectic ZA: identified as an orientationally ordered, antiferroelectric phase with a density modulation in direction perpendicular to the optic axis. At even higher temperatures, this transitions to an apparently normal nematic phase. We have studied the splay-bend Freedericksz transition in the nematic and SmZA phases of the material DIO. Both the magnetic and electric field transitions were utilized. We observed the transitions by measuring effective birefringence and capacitance as well as with polarizing light microscopy. In both the nematic and the SmZA states the field induced transitions resemble (in numerous aspects) the classical Freedericksz transition. These enable determinations of several fundamental material parameters and also reveal intriguing aspects of the SmZA phase, including the surprising behavior of the elastic constants and the dielectric anisotropy. Detailed comparison with Frank elastic theory of the Freedericksz transition shows that the N phase behaves largely as expected, but the transition in the SmZA phase differs significantly. Two specific examples of this are the onset of striations in the Freedericksz distorted state, and the presence of optical biaxiality. The former may be related to the periodic Freedericksz transition as it coincides with a large increase in the splay elastic constant. The latter has been predicted for the SmZA phase, but not previously observed.

We study nonreciprocal signatures of Josephson current (JC) in a quantum dot (QD)-based Josephson junction (JJ) that comprises of two periodically driven Kitaev chains (KCs) coupled with an intervening QD. The simultaneous breaking of the inversion symmetry ($\mathcal{IS}$) and the time-reversal symmetry ($\mathcal{TRS}$), indispensable for the Josephson diode effect (JDE), is achieved solely via the two Floquet drives that differ by a finite phase, which eventually results in a nonreciprocal current, and hence yields a finite JDE. It may be noted that the Floquet Majorana modes generated at both the far ends of the KCs (away from the QD) and adjacent to the QD junctions mediate the JC owing to a finite superconducting (SC) phase difference in the two KCs. We calculate the time-averaged JC and inspect the tunability of the current-phase relation (CPR) to ascertain the diode characteristics. The asymmetric Floquet drive also manifests an anomalous JC signature in our KC-QD-KC JJ. Furthermore, additional control over the QD energy level can be achieved via an external gate voltage that renders flexibility for the Josephson diode (JD) to act as an SC switching device. Tuning different system parameters, such as the chemical potential of the KCs, Floquet frequency, the relative phase mismatch of the drives, and the gate voltage, our model shows the highest possible rectification to be around $70\%$. Summarizing, our study provides an alternative scenario, replacing the traditional usage of an external magnetic field and spin-orbit coupling effects in a JD via asymmetrically driven Kitaev leads that entail Majorana-mediated transport.

Yielding of amorphous glasses and gels is a mechanically driven transformation of a material from the solid to liquid state on the experimental timescale. It is a ubiquitous fundamental problem of nonequilibrium physics of high importance in material science, biology, and engineering applications such as processing, ink printing, and manufacturing. However, the underlying microscopic mechanisms and degree of universality of the yielding problem remain theoretically poorly understood. We address this problem for dense Brownian suspensions of nanoparticles or colloids that interact via repulsions that induce steric caging and tunable short range attractions that drive physical bond formation. In the absence of deformation, these competing forces can result in fluids, repulsive glasses, attractive glasses, and dense gels of widely varying elastic rigidity and viscosity. Building on a quiescent microscopic theoretical approach that explicitly treats attractive bonding and thermally-induced activated hopping, we formulate a self-consistent theory for the coupled evolution of the transient and steady state mechanical response, and structure as a function of stress, strain, and deformation rate over a wide range of high packing fractions and attraction strengths and ranges. Depending on the latter variables, under step rate shear the theory predicts three qualitatively different transient responses: plastic-like (of two distinct types), static yielding via a single elastic-viscous stress overshoot, and double or 2-step yielding due to an intricate competition between deformation-induced bond breaking and de-caging. A predictive understanding of multiple puzzling experimental observations is achieved, and the approach can be extended to other nonlinear rheological protocols and soft matter systems.

In this work, we perform ultrafast time-resolved reflectivity measurements to study the symmetry breaking in the charge-density wave (CDW) phase of CsV$_3$Sb$_5$. By extracting the coherent phonon spectrum in the CDW phase of CsV$_3$Sb$_5$, we discover close phonon pairs near 1.3 THz and 3.1 THz, as well as a new mode at 1.84 THz. The 1.3 THz phonon pair and the 1.84 THz mode are observed up to the CDW transition temperature. Combining density-functional theory calculations, we point out these phonon pairs arise from the coexistence of Star-of-David and inverse Star-of-David distortions combined with six-fold rotational symmetry breaking. An anisotropy in the magnitude of transient reflectivity change is also revealed at the onset of CDW order. Our results thus indicate broken six-fold rotational symmetry in the charge-density wave state of CsV$_3$Sb$_5$, along with the absence of nematic fluctuation above T$_{\text{CDW}}$. Meanwhile, the measured coherent phonon spectrum in the CDW phase of CsV$_3$Sb$_{5-\text{x}}$Sn$_\text{x}$ with x = 0.03-0.04 matches with staggered inverse Star-of-David with interlayer $\pi$ phase shift. This CDW structure contrasts with undoped CsV$_3$Sb$_5$ and explains the evolution from phonon pair to a single mode at 1.3 THz by x = 0.03-0.04 Sn-doping.

The presence of quasiparticles typically degrades the performance of superconducting microwave circuits. The readout signal can generate non-equilibrium quasiparticles, which lead to excess microwave loss and decoherence. To understand this effect quantitatively, we measure quasiparticle fluctuations and extract the quasiparticle density across different temperatures, readout powers, and resonator volumes. We find that microwave power generates a higher quasiparticle density as the active resonator volume is reduced and show that this effect sets a sensitivity limit on kinetic inductance detectors. We compare our results with theoretical models of direct microwave photon absorption by quasiparticles and conclude that an unknown, indirect mechanism plays a dominant role in quasiparticle generation. These results provide a route to mitigate quasiparticle generation due to readout power in superconducting devices.

Optoionics, a promising new field that aims at controlling ion dynamics using light, links photovoltaic power generation with electrochemical charge storage. This has the potential to drive and accelerate the energy revolution by utilizing materials that integrate the functionality of batteriesand photovoltaic cells. Finding, optimizing, and customizing these materials is a complex task, though. Computational modeling can play a crucial role in guiding and speeding up these processes, particularly when the atomic mechanisms are not well understood. This does however require expertise in various areas, including advanced electronic-structure theory, machine learning, and multi-scale approaches. In this perspective, we shed light on the intricacies of modeling optoionic effects for solar battery materials. We first discuss the underlying physical and chemical mechanisms, as well as the computational tools that are available to date for describing these processes. Furthermore, we discuss the limits of these approaches and identify key challenges that need to be tackled to advance this field.

The recently discovered Kagome superconductor AV$_3$Sb$_5$ (where A refers to K, Rb, Cs) has stimulated widespread research interest due to its interplay of non-trivial topology and unconventional correlated physics including charge-density waves (CDW) and superconductivity. The essential prerequisite to understanding the microscopic mechanisms of this complex electronic landscape is to unveil the configuration and symmetry of the charge-density wave order. As to now, little consensus has been made on what symmetry is broken. Herein, we clarify the microscopic structure and symmetry breaking of the CDW phase in RbV$_3$Sb$_5$ and KV$_3$Sb$_5$ by ultrafast time-resolved reflectivity. Our approach is based on extracting coherent phonon spectra induced by three-dimensional CDW and comparing them to calculated phonon frequencies via density-functional theory. The combination of these experimental results and calculations provides compelling evidence that the CDW structure of both compounds prevailing up to T$_{\text{CDW}}$ is the 2 $\times$ 2 $\times$ 2 staggered inverse Star-of-David pattern with interlayer $\pi$ phase shift, in which the six-fold rotational symmetry is broken. These observations thus corroborate six-fold rotational symmetry breaking throughout the CDW phase of RbV$_3$Sb$_5$ and KV$_3$Sb$_5$.

We employed molecular dynamics simulations to explore comparatively the thermo-mechanical behavior of two glass materials-an oxide silica glass (SiO2) and a binary Cu-Zr-based metallic alloy (Cu50Zr50)-during shear deformation cycles. By calculating the energy balance and tracking the temperature evolution of both glasses under deformation cycles, we are able to propose, for each of them, a constitutive law which accurately reproduces the self-heating process due to plastic deformation. These relatively simple constitutive laws involve strain rate sensitivity and a non-linear temperature dependence of the thermal dilatancy coefficients, as well as strain gradient plasticity. To identify the right parameters, both glasses are equilibrated at very low temperature (10 K) and two independent deformation rates were applied to each sample. Thermal attenuation is greatly amplified in silica compared to the metallic glass. Moreover, using precise atomic description of the instantaneous deformation, combined with exact coarse-graining procedure, we show that selfheating is mainly supported, in silica, by inhomogeneous strain gradient plasticity with nanometric characteristic lengthscales.

Since Hertz's pioneering work in 1882, contact mechanics traditionally grounds on linear elasticity, assuming small strains and displacements. However, recent experiments clearly highlighted linear elasticity limitations in accurately predicting the contact behaviour of rubbers and elastomers, particularly during frictional slip, which is governed by geometric and material nonlinearity. In this study, we investigate the basic scenario involving normal approach-retraction contact cycles between a wavy rigid indenter and a flat, deformable substrate. Both frictionless and frictional interfacial conditions are examined, considering finite strains, displacements, and nonlinear rheology. We developed a finite element model for this purpose and compared our numerical results with Westergaard's linear theory. Our findings show that, even in frictionless conditions, the contact response is significantly influenced by geometric and material nonlinearity, particularly for wavy indenters with high aspect ratios, where normal-tangential stresses and displacements coupling emerges. More importantly, interfacial friction in nonlinear elasticity leads to contact hysteresis (i.e., frictional energy dissipation) during normal loading-unloading cycles. This behavior cannot be explained in a linear framework; therefore, most of the experiments reporting hysteresis are typically explained invoking other interfacial phenomena (e.g., adhesion, plasticity, or viscoelasticity). Here we present an additional suitable explanation relying on finite strains/displacements with detailed peculiarities, such as vanishing pull-off force. Moreover, we also report an increase of hysteretic losses as for confined systems, stemming from the enhanced normal-tangential nonlinear coupling.

Two-dimensional (2D) Ruddlesden-Popper (RP) Metal Halides present unique and tunable properties, offering a plethora of applications in optoelectronics. However, the direct and oriented synthesis of these materials is challenging due to the low formation energies that result in fast, uncontrollable growth dynamics during solution-based processing. Here, we report the solvent-free growth of oriented and n = 1 2D $(\mbox{PEA})_2\mbox{PbI}_4$ RP films by pulsed laser deposition (PLD). In situ photoluminescence (PL) during PLD reveal that the n =1 RP phase of $(\mbox{PEA})_2\mbox{PbI}_4$ forms at the first stages of growth. X-ray diffraction (XRD) and grazing-incidence wide-angle scattering (GIWAXS) measurements confirm the formation of single oriented n = 1 phase of $(\mbox{PEA})_2\mbox{PbI}_4$ independent of the underlying substrate. Co-localized spatially resolved PL and AFM further validate the conformal growth of the n = 1 phase. While oriented growth is substrate-independent, the stability of the 2D films is influenced by the substrate. PLD-grown 2D RP films grown onto epitaxial $\mbox{MAPbI}_3$ films are stable over 80 days, showing no sign of cation exchange. This work highlights the potential of PLD for direct, room-temperature synthesis of 2D $(\mbox{PEA})_2\mbox{PbI}_4$ RP films on diverse substrates and demonstrates the feasibility of stable 2D/3D heterostructures.

In this work, the cryoscopic decrease effect, as a function of the NaCl concentration, on the carbon dioxide (CO$_2$) hydrate dissociation line conditions has been determined through molecular dynamic simulations. In particular, we have determined the three-phase (solid hydrate-aqueous phase-liquid CO$_2$) coexistence temperature at 100, 400, and 1000 at several initial NaCl concentrations in the aqueous phase, from 0.0 to $3.0\,\text{m}$, using the direct-coexistence technique. We have used the well-known TIP4P/2005 and TraPPE force fields for water and CO$_2$ molecules, respectively. Also, the water-salt interactions are described using the Madrid-2019 force field, which has been specifically developed for various salts in combination with the TIP4P/2005 water model. According to the results obtained in this work, the dissociation temperature of the CO$_2$ hydrate decreases when the NaCl concentration in the initial aqueous phase increases. The results obtained are in excellent agreement with experimental data reported in the literature. We have also observed how the dynamic of melting and growth of the CO$_2$ hydrate becomes slower when the NaCl concentration is increased. As a consequence, larger simulation times (in the order of dozens of microseconds) are necessary when the NaCl concentration increases. Finally, we have also analyzed finite-size effects on the three-phase coexistence temperature of these systems by performing simulations, at 400 bar, with two different system sizes at two different NaCl concentrations (0.0 and $3.0\,\text{m}$). Non-negligible deviations have been found between the results obtained from both system sizes.

Screened spherical wave (SSW) of the Hankel function features the complete, minimal and short-ranged basis set, presenting a compact representation for electronic systems. In this work, we report the implementation of full-potential (FP) SSW based tight-binding linearized Muffin-Tin orbital (TB-LMTO) for all-electron density functional theory (DFT), and provide extensive tests on the robustness of FP-TB-LMTO and its high accuracy for first-principles material simulation. Through the introduction of double augmentation, SSW based MTO is accurately represented on the double grids including the full-space uniform and dense radial grids. Based on the the double augmentation, the accurate computation of full charge density, full potential,complex integral in the interstitial region and the total energy are all effectively addressed to realize the FP-TB-LMTO for DFT self-consistent calculations. By calculating the total energy,band structure, phase ordering, and elastic constants for a wide variety of materials, including normal metals, compounds, and diamond silicon, we domenstrate the highly accurate numerical implemetation of FP-TB-LMTO for all-electron DFT in comparison with other well-established FP method. The implementation of FP-TB-LMTO based DFT offers an important tool for the accurate first-principles tight-binding electronic structure calculations, particular important for the large-scale or strongly correlated materials.

Modelling has become a third distinct line of scientific enquiry, alongside experiments and theory. Molecular dynamics (MD) simulations serve to interpret, predict and guide experiments and to test and develop theories. A major limiting factor of MD simulations is system size and in particular the difficulty in handling, storing and processing trajectories of very large systems. This limitation has become significant as the need to simulate large system sizes of the order of billions of atoms and beyond has been steadily growing. Examples include interface phenomena, composite materials, biomaterials, melting, nucleation, atomic transport, adhesion, radiation damage and fracture. More generally, accessing new length and energy scales often brings qualitatively new science, but this has currently reached a bottleneck in MD simulations due to the traditional methods of storing and post-processing trajectory files. To address this challenge, we propose a new paradigm of running MD simulations: instead of storing and post-processing trajectory files, we calculate key system properties on-the-fly. Here, we discuss the implementation of this idea and on-the-fly calculation of key system properties in the general-purpose MD code, DL_POLY. We discuss code development, new capabilities and the calculation of these properties, including correlation functions, viscosity, thermal conductivity and elastic constants. We give examples of these on-the-fly calculations in very large systems. Our developments offer a new way to run MD simulations of large systems efficiently in the future.

An efficient mixed deterministic/sparse-stochastic plane-wave approach is developed for bandstructure calculations of large supercell periodic generalized-Kohn-Sham density functional theory, for any hybrid-exchange density functional. The method works for very large elementary cells and supercells, and we benchmark it on covalently bonded solids and molecular crystals with nonbonded interactions, for supercells of up to 33,000 atoms. Memory and CPU requirements scale with supercell size quasi-linearly.

Non-diffusive, hydrodynamic-like transport of charge or heat has been observed in several materials, and recent, pioneering experiments have suggested the possible emergence of electron-phonon bifluids. Here we introduce the first-principles theory and computational framework to describe these phenomena, showing that the viscosity of electron-phonon bifluids is microscopically determined by composite ``relaxon'' electron-phonon excitations that also describe electron-phonon drag effects on thermoelectric transport coefficients. We show that these composite excitations emerge from the microscopic coupled electron-phonon Boltzmann transport equation, and demonstrate that the latter can be coarse-grained into a set of mesoscopic Viscous Thermoelectric Equations (VTE). The VTE unify the established hydrodynamic equation for electrons derived by Gurzhi [Sov. Phys. Usp. 11 1968], and the recently developed Viscous Heat Equations for phonons [PRX 10, 2020], while also extending them to cover the mixed electron-phonon bifluid regime. We employ this framework to elucidate from first principles the conditions under which electron and phonon fluids can coexist and mix, as well as to rationalize experimental signatures of electron-phonon drag in graphite.

Topological semimetals, particularly Weyl semimetals (WSMs), are crucial platforms for exploring emergent quantum phenomena due to their unique electronic structures and potential to transition into various topological phases. In this study, we report the discovery of a ferromagnetic (FM) type-II WSM in Mn(Bi1-xSbx)4Te7, which exhibits a remarkable three-dimensional (3D) quantum Hall effect (QHE). By precisely tuning the chemical potential through Sb doping, we obtained samples with the Fermi level near the charge neutrality point for x = ~ 0.27. This was confirmed by spectroscopy measurements (ARPES and STS), and these samples showed strong quantum oscillations along with a key transport signature of a Weyl state - chiral anomaly, and Fermi surface reconstruction driven by FM ordering. Our theoretical analysis indicates that this Weyl state evolves from a parent nodal ring state, where higher-order k-terms split the nodal line into type-II Weyl nodes. The Weyl state exhibits significant anisotropy, characterized by a pronounced reduction in Fermi velocity along the kz-axis, likely accounting for the observed 3D QHE. These results not only highlight the exceptional tunability of the Mn(Bi1-xSbx)4Te7 system, where precise control of the chemical potential and magnetic properties opens access to novel quantum phases, but also advance the understanding of FM WSMs.

Interactions between active particles may be non-reciprocal, breaking action-reaction symmetry and leading to novel physics not seen in equilibrium systems. In this work, we study the phase diagram for the non-reciprocal Cahn-Hilliard (NRCH) model with different types of symmetry -- discrete and continuous -- and examine the effects of non-reciprocity on phase separation. The models are analyzed by drawing the full linear stability diagrams, indicating the onset of phase separation, allowing us to demonstrate how non-reciprocity gives rise to out-of-equilibrium steady states with non-zero currents. These observations are robust to noise and valid in a large part of parameter space. By describing the effects of symmetry on conserved, non-reciprocal models, this work adds to our understanding of the rich phase-behavior of such models.

Deep generative models have recently been proposed for sampling protein conformations from the Boltzmann distribution, as an alternative to often prohibitively expensive Molecular Dynamics simulations. However, current state-of-the-art approaches rely on fine-tuning pre-trained folding models and evolutionary sequence information, limiting their applicability and efficiency, and introducing potential biases. In this work, we propose a flow matching model for sampling protein conformations based solely on backbone geometry. We introduce a geometric encoding of the backbone equilibrium structure as input and propose to condition not only the flow but also the prior distribution on the respective equilibrium structure, eliminating the need for evolutionary information. The resulting model is orders of magnitudes faster than current state-of-the-art approaches at comparable accuracy and can be trained from scratch in a few GPU days. In our experiments, we demonstrate that the proposed model achieves competitive performance with reduced inference time, across not only an established benchmark of naturally occurring proteins but also de novo proteins, for which evolutionary information is scarce.

The natural interactive materials under far-from-equilibrium conditions have significantly inspired advances in synthetic biomimetic materials. In artificial systems, gradient diffusion serves as the primary means of interaction between individuals, lacking directionality, sufficient interaction ranges and transmission rates. Here, we present a method for constructing highly directed, communicative structures via optical feedback in light responsive materials. We showcase a photomechanical operator system comprising a baffle and a soft actuator. Positive and negative operators are configured to induce light-triggered deformations, alternately interrupting the passage of two light beams in a closed feedback loop. The fundamental functionalities of this optically interconnected material loop include homeostasis-like self-oscillation and signal transmission from one material to another via light. Refinements in alignment facilitate remote sensing, fiber-optic/long-distance communication, and adaptation. These proof-of-concept demonstrations outline a versatile design framework for light-mediated communication among responsive materials, with broad applicability across diverse materials.

Purpose: Depending on the road surface profile, moving speed, transport weight, etc., the vehicle's body acceleration and dynamic load coefficient change as it moves. This study's goal is to ascertain the result of the road surface's influence on the vehicle, calculate the average vehicle body displacement acceleration and dynamic load coefficient, and validate your findings through testing. To confirm the simulation model's accuracy, experimental and theoretical simulation results are compared.. Methods: The Neuton-Euler approach and the multi-body system structure separation method are used in the paper to create dynamic equations using theoretical research methods [1]. Simulations are carried out using Matlab Simulink software to examine and assess the dynamics. Results: According to ISO 8608:2016 standard [2], theoretical research results have determined the average acceleration of the vehicle body, dynamic load coefficient, horizontal sway angle, and longitudinal sway angle when the vehicle moves on profiles C, D , E, F. Experiments show that there is an error of 7.4% and 8.1% when measuring the average acceleration and dynamic load coefficient k{\dj}max when the vehicle moves at a speed of 50 km/h on the road surface C compared to theory.

Materials foundation models can predict energy, force, and stress of materials and enable a wide range of downstream discovery tasks. A key design choice involves the trade-off between invariant and equivariant architectures. Invariant models offer computational efficiency but may not perform well when predicting high-order outputs. In contrast, equivariant models can capture high-order symmetries, but are computationally expensive. In this work, we propose HIENet, a hybrid invariant-equivariant foundation model that integrates both invariant and equivariant message passing layers. HIENet is designed to achieve superior performance with considerable computational speedups over prior models. Experimental results on both common benchmarks and downstream materials discovery tasks demonstrate the efficiency and effectiveness of HIENet.

Nucleation in the supercooled Yukawa system is relevant for addressing current challenges in understanding a range of crystallizing systems including white dwarf (WD) stars. We use both brute force and seeded molecular dynamics simulations to study homogeneous nucleation of crystals from supercooled Yukawa liquids. With our improved approach to seeded simulations, we obtain quantitative predictions of the crystal nucleation rate and cluster size distributions as a function of temperature and screening length. These quantitative results show trends towards fast nucleation with short-ranged potentials. They also indicate that for temperatures $T > 0.9T_m$, where $T_m$ is the melt temperature, classical homogeneous nucleation is too slow to initiate crystallization but transient clusters of around 100 particles should be common. We apply these general results to a typical WD model and obtain a delay of approximately 0.6 Gyr in the onset of crystallization that may be observable.

We study the double kicked top (DKT), which is an extension of the standard quantum kicked top (QKT) model. The model allows us to study the transition from time-reversal symmetric to broken time-reversal symmetric dynamics. Our transformation in the kick strength parameter space $(k, k') \to (k_r, k_\theta)$ reveals interesting features. The transformed kicked strength parameter $k_r$ drives a higher growth of chaos and is equivalent to the standard QKT, whereas the other transformed kicked strength parameter $k_\theta$ leads to a weaker growth. We discuss the fixed points, their stability, and verify results obtained by computing the largest Lyapunov exponent (LLE) and the Kolmogorov-Sinai entropy (KSE). We exactly solve 2- to 4-qubit versions of DKT by obtaining its eigenvalues, eigenvectors and the entanglement dynamics. Furthermore, we find the criteria for periodicity of the entanglement dynamics. We investigate measures of quantum correlations from two perspectives: the deep quantum and the semi-classical regime. Signatures of phase-space structure are numerically shown in the long-time averages of the quantum correlations. Our model can be realised experimentally as an extension of the standard QKT.

Interactions between crawling cells, which are essential for many biological processes, can be quantified by measuring cell-cell collisions. Conventionally, experiments of cell-cell collisions are conducted on two-dimensional flat substrates, where colliding cells repolarize and move away upon contact with one another in "contact inhibition of locomotion" (CIL). Inspired by recent experiments that show cells on suspended nanofibers have qualitatively different CIL behaviors than those on flat substrates, we develop a phase field model of cell motility and two-cell collisions in fiber geometries. Our model includes cell-cell and cell-fiber adhesion, and a simple positive feedback mechanism of cell polarity. We focus on cell collisions on two parallel fibers, finding that larger cell deformability (lower membrane tension), larger positive feedback of polarization, and larger fiber spacing promote more occurrences of cells walking past one another. We can capture this behavior using a simple linear stability analysis on the cell-cell interface upon collision.

Phase transitions of matter under changes of external environment such as temperature and magnetic field have attracted great interests to various quantum many-body systems. Several phase transitions must have occurred in neutron stars as well such as transitions from normal to superfluid/superconducting phases and crust formation. In this work, we extend the superfluid band theory, which has been formulated in our previous work [K. Yoshimura and K. Sekizawa, Phys. Rev. C 109, 065804 (2024)] based on the Kohn-Sham density functional theory (DFT) for superfluid systems, into the finite temperature and finite magnetic field systems. As a result of the finite temperature calculations, we find that the superfluidity of neutrons dissapears at around $k_\text{B}T=0.6$--$0.9\,$ MeV, and ``melting'' of nuclear slabs, that is, a structural change into the uniform matter, takes place at around $k_\text{B}T=2.5$--$4.5\,$ MeV. We also reveal that these transition temperatures exhibit a systematical dependence on the baryon densities. By turning on the magnetic field, we find that protons' spin gets polarized at around $B=10^{16}\,$G, whereas neutrons' spin is kept unpolarized on average up to around $B=10^{17}\,$G. Intriguingly, our microscopic calculations reveal that neutrons' spin is actually polarized locally inside and outside of the slab already at $B\sim10^{16}\,$G, while keeping the system unpolarized in total. As a conclusion, we have demonstrated validity and usefulness of the fully self-consistent superfluid nuclear band theory for describing neutron star matter under arbitrary temperature and magnetic field. Critical temperatures and magnetic fields have been predicted for 1) superfluid to normal transition, 2) crust formation, and 3) spin polarization, under conditions relevant to realistic neutron star environments.

It is known for some time that autocorrelations of words in human-written texts decay according to a power law. Recent works have also shown that the autocorrelations decay in texts generated by LLMs is qualitatively different from the literary texts. Solid state physics tie the autocorrelations decay laws to the states of matter. In this work, we empirically demonstrate that, depending on the temperature parameter, LLMs can generate text that can be classified as solid, critical state or gas.

We propose a stochastic sampling approach to identify stability boundaries in general dynamical systems. The global landscape of Lyapunov exponent in multi-dimensional parameter space provides transition boundaries for stable/unstable trajectories, i.e., the edge of chaos. Despite its usefulness, it is generally difficult to derive analytically. In this study, we reveal the transition boundaries by leveraging the Markov chain Monte Carlo algorithm coupled directly with the numerical integration of nonlinear differential/difference equation. It is demonstrated that a posteriori modeling for parameter subspace along the edge of chaos determines an inherent constrained dynamical system to flexibly activate or de-activate the chaotic tra jectories.

Simulations of nematohydrodynamics on graphics processing units (GPUs) are typically performed using double precision, which ensures accuracy but significantly increases computational cost. However, consumer-grade GPUs are optimized for single-precision calculations, making double-precision simulations inefficient on widely available hardware. In this work, we demonstrate that single-precision simulations can achieve the same accuracy as double-precision methods while delivering a 27-fold increase in computational speed. To achieve this, we introduce two key improvements: (i) the shifted distribution function in the lattice Boltzmann method, which mitigates precision loss at low velocities, and (ii) the use of larger time steps in the finite-difference solver, which reduces numerical errors and improves overall accuracy. We find that, unlike in double precision, accuracy in single-precision simulations follows a non-monotonic trend with respect to the finite-difference time step, revealing an optimal regime for precise computations. To illustrate the effectiveness of our approach, we simulate the dynamics of single and multiple skyrmionic tubes in Poiseuille flow. Our results confirm that optimized single-precision simulations enable fast and accurate modeling of complex nematohydrodynamic systems, making large-scale simulations feasible on standard gaming GPUs.

Quantum many-body scars have received much recent attention for being both intriguing non-ergodic states in otherwise quantum chaotic systems and promising candidates to encode quantum information efficiently. So far, these studies have mostly been restricted to Hermitian systems. Here, we study many-body scars in many-body quantum chaotic systems coupled to a Markovian bath, which we term Lindblad many-body scars. They are defined as simultaneous eigenvectors of the Hamiltonian and dissipative parts of the vectorized Liouvillian. Importantly, because their eigenvalues are purely real, they are not related to revivals. The number and nature of the scars depend on both the symmetry of the Hamiltonian and the choice of jump operators. For a dissipative four-body Sachdev-Ye-Kitaev (SYK) model with $N$ fermions, either Majorana or complex, we construct analytically some of these Lindblad scars while others could only be obtained numerically. As an example of the former, we identify $N/2+1$ scars for complex fermions due to the $U(1)$ symmetry of the model and two scars for Majorana fermions as a consequence of the parity symmetry. Similar results are obtained for a dissipative XXZ spin chain. We also characterize the physical properties of Lindblad scars. First, the operator size is independent of the disorder realization and has a vanishing variance. By contrast, the operator size for non-scarred states, believed to be quantum chaotic, is well described by a distribution centered around a specific size and a finite variance, which could be relevant for a precise definition of the eigenstate thermalization hypothesis in dissipative quantum chaos. Moreover, the entanglement entropy of these scars has distinct features such as a strong dependence on the partition choice and, in certain cases, a large entanglement.

Unified generation of sequence and structure for scientific data (e.g., materials, molecules, proteins) is a critical task. Existing approaches primarily rely on either autoregressive sequence models or diffusion models, each offering distinct advantages and facing notable limitations. Autoregressive models, such as GPT, Llama, and Phi-4, have demonstrated remarkable success in natural language generation and have been extended to multimodal tasks (e.g., image, video, and audio) using advanced encoders like VQ-VAE to represent complex modalities as discrete sequences. However, their direct application to scientific domains is challenging due to the high precision requirements and the diverse nature of scientific data. On the other hand, diffusion models excel at generating high-dimensional scientific data, such as protein, molecule, and material structures, with remarkable accuracy. Yet, their inability to effectively model sequences limits their potential as general-purpose multimodal foundation models. To address these challenges, we propose UniGenX, a unified framework that combines autoregressive next-token prediction with conditional diffusion models. This integration leverages the strengths of autoregressive models to ease the training of conditional diffusion models, while diffusion-based generative heads enhance the precision of autoregressive predictions. We validate the effectiveness of UniGenX on material and small molecule generation tasks, achieving a significant leap in state-of-the-art performance for material crystal structure prediction and establishing new state-of-the-art results for small molecule structure prediction, de novo design, and conditional generation. Notably, UniGenX demonstrates significant improvements, especially in handling long sequences for complex structures, showcasing its efficacy as a versatile tool for scientific data generation.

In their study of Levin-Wen models [Commun. Math. Phys. 313 (2012) 351-373], Kitaev and Kong proposed a weak Hopf algebra associated with a unitary fusion category $\mathcal{C}$ and a unitary left $\mathcal{C}$-module $\mathcal{M}$, and sketched a proof that its representation category is monoidally equivalent to the unitary $\mathcal{C}$-module functor category $\mathrm{Fun}^{\mathrm{u}}_{\mathcal{C}}(\mathcal{M},\mathcal{M})^\mathrm{rev}$. We give an independent proof of this result without the unitarity conditions. In particular, viewing $\mathcal{C}$ as a left $\mathcal{C} \boxtimes \mathcal{C}^{\mathrm{rev}}$-module, we obtain a quasi-triangular weak Hopf algebra whose representation category is braided equivalent to the Drinfeld center $\mathcal{Z}(\mathcal{C})$. In the appendix, we also compare this quasi-triangular weak Hopf algebra with the tube algebra $\mathrm{Tube}_{\mathcal{C}}$ of $\mathcal{C}$ when $\mathcal{C}$ is pivotal. These two algebras are Morita equivalent by the well-known equivalence $\mathrm{Rep}(\mathrm{Tube}_{\mathcal{C}})\cong\mathcal{Z}(\mathcal{C})$. However, we show that in general there is no weak Hopf algebra structure on $\mathrm{Tube}_{\mathcal{C}}$ such that the above equivalence is monoidal.

We present a novel method that combines spin resonance spectroscopy with transmission electron microscopy (TEM), enabling localized in-situ detection of microwave (MW)-driven spin excitations. Our approach utilizes continuous wave MW excitation at GHz frequencies, while employing the free-space electron beam as a signal receiver to sense spin precession. Spin state polarization is achieved via the magnetic field of the TEM's polepiece, while a custom-designed microresonator integrated into a TEM sample holder drives spin transitions and modulates the electron beam. This modulation enables phase-locked detection with picosecond temporal resolution, allowing the isolation of spin precession contributions to the electron beam deflection with a sensitivity of $\sim 280$ prad. The presented technique lays foundations for the MW spectroscopic in-situ exploration of spin dynamics at the nanoscale.

The use of nuclear spins for quantum computation is limited by the difficulty in creating genuine quantum entanglement between distant nuclei. Current demonstrations of nuclear entanglement in semiconductors rely upon coupling the nuclei to a common electron, which is not a scalable strategy. Here we demonstrate a two-qubit Control-Z logic operation between the nuclei of two phosphorus atoms in a silicon device, separated by up to 20 nanometers. Each atoms binds separate electrons, whose exchange interaction mediates the nuclear two-qubit gate. We prove that the nuclei are entangled by preparing and measuring Bell states with a fidelity of 76 +/- 5 $\%$ and a concurrence of 0.67 +/- 0.05. With this method, future progress in scaling up semiconductor spin qubits can be extended to the development of nuclear-spin based quantum computers.

Real quantum systems can exhibit a local object called local partial density of states (LPDOS) that cannot be proved within the axiomatic approach of quantum mechanics. We demonstrate that real mesoscopic system that can exhibit Fano resonances will show this object and also very counterintuitively it can become negative, resulting in the enhancement of coherent currents.

We theoretically investigate Cooper quartet correlations in $ N = Z $ doubly-magic nuclei ($ {}^{40} \mathrm{Ca} $, $ {}^{100} \mathrm{Sn} $, and $ {}^{164} \mathrm{Pb} $). We first examine the quartet condensation fraction in infinite symmetric nuclear matter by using the quartet Bardeen-Cooper-Schrieffer theory. Together with the total nucleon density profiles of doubly-magic nuclei obtained from the Skyrme Hartree-Fock calculation, we discuss the spatial distribution of quartet correlations in finite nuclei within the local density approximation. Large quartet condensate fractions are found at the surface region of an atomic nucleus due to the strong neutron-proton attractive interactions responsible for the deuteron formation in vacuum. Moreover, we discuss a possible microscopic origin of the Wigner term in the context of nucleon-quartet scattering in dilute symmetric nuclear matter. The nucleon-quartet scattering effect on the Wigner term is numerically estimated as about one order of magnitude of the total empirical strength, indicating the importance of multi-nucleon clusters in the symmetry energy and mass formula in addition to the neutron-proton pairing.

Inspired by the one-dimensional color-electric flux-tube in a hadron, we propose a possible way of low-dimensionalization of 4D QCD. As a strategy, we use gauge degrees of freedom and propose a new gauge fixing of ``dimensional reduction (DR) gauge". The DR gauge is defined so as to minimize $R_{\rm DR} \equiv \int d^4s~{\rm Tr}~[A^2_x(s)+A^2_y(s)]$, which preserves the 2D SU($N_{c}$) gauge symmetry. We investigate low-dimensionalization properties of 4D DR-gauged QCD in SU(3) lattice QCD at $\beta$ = 6.0. In the DR gauge, the amplitudes of two gluon components $A_{x}(s)$ and $A_{y}(s)$ are found to be strongly suppressed, and these components have a large effective mass of $M_{\perp} \simeq 1.7$ GeV. In the DR gauge, the static interquark potential is well reproduced only with the two components $A_{t}(s)$ and $A_{z}(s)$, while $A_{x}(s)$ and $A_{y}(s)$ seem to be inactive. We investigate the spatial correlation of two $t$-directed gluons and find that the correlation decreases as $e^{-mr}$ with $m \simeq$ 0.64 GeV, corresponding to the correlation length $\xi \equiv 1/m \simeq$ 0.31 fm. We reduce 4D QCD in the DR gauge to 2D QCD with the coupling $g_{2D} = g/\xi$, which approximately reproduces the string tension.

We present a template for realization of a novel microengine which is able to harness and convert the activity driven movement of individual motor protein into work output of the system. This engine comprises of a micron size bead-motor protein complex that is subject to a time-varying, feedback controlled optical potential, and a driving force due to the action of the motor protein which stochastically binds, walks and unbinds to an underlying microtubule filament. Using a Stochastic thermodynamics framework and theoretical modeling of bead-motor transport in a harmonic optical trap potential, we obtain the engine characteristics, e.g., work output per cycle, power generated, efficiency and the probability distribution function of the work output as a function of motor parameters and optical trap stiffness. The proposed engine is a work-to-work converter. Remarkably, the performance of this engine can vastly supersede the performance of other microengines that have been realized so far for feasible biological parameter range for kinesin-1 and kinesin-3 motor proteins. In particular, the work output per cycle is ~ (10-15) k_b T while the power output is (5-8) k_b T s^{-1}. Furthermore, we find that even with time delay in feedback protocol, the performance of the engine remains robust as long as the delay time is much smaller than the Brownian relaxation time of the micron size bead. Indeed such low delay time in feedback in the optical trap setup can easily be achieved with current Infrared (IR) lasers and optical trap sensor. The average work output and power output of the engine, exhibits interesting non-monotonic dependence on motor velocity and optical trap stiffness. As such this motor protein driven microengine can be a promising potential prototype for fabricating an actual microdevice engine which can have practical utility.

The interplay of topology and disorder in quantum dynamics has recently attracted significant attention across diverse platforms, including solid-state devices, ultracold atoms, and photonic systems. Here, we report on a topological Anderson transition caused by quasiperiodic inter-cell coupling disorder in photonic Su-Schrieffer-Heeger lattices. As the quasiperiodic strength is varied, the system exhibits a reentrant transition from a trivial phase to a topological phase and back to a trivial phase. Unlike the traditional detection of photonic topological edge modes, we measure the mean chiral displacement from the transport of light in the bulk of the lattices. In our photonic lattices with a fixed length, the propagation dynamics is retrieved by varying the wavelength of light, which tunes the inter-waveguide couplings.

Rayleigh-L\'evy flights are simplified cosmological tools which capture certain essential statistical properties of the cosmic density field, including hierarchical structures in higher-order correlations, making them a valuable reference for studying the highly non-linear regime of structure formation. Unlike standard Markovian processes, they exhibit long-range correlations at all orders. Following on recent work on one dimensional flights, this study explores the one-point statistics and Minkowski functionals (density PDF, perimeter, Euler characteristic) of Rayleigh-L\'evy flights in two dimensions. We derive the Euler characteristic in the mean field approximation and the density PDF and iso-field perimeter $W_{1}$ in beyond mean field calculations, and validate the results against simulations. The match is excellent throughout, even for fields with large variances, in particular when finite volume effects in the simulations are taken into account and when the calculation is extended beyond the mean field.

In this article, we investigate the thermal properties of non-relativistic many-body systems at finite temperature and chemical potential. We compute the one-point function of various operators constructed out of the basic fields in ideal bosonic and fermionic many-body systems. The one-point function is non-zero only for operators with zero particle numbers. We investigate these operators in $\mathbb R^d$ and $\mathbb R^d_{+}$, i.e. a flat space with a planar boundary. Furthermore, we compute the Green's function and using the operator product expansion, we express it in terms of the thermal one-point function of the higher spin currents. On $\mathbb R^d_{+}$, the operator product expansion allows to express the bulk-bulk Green's function in terms of the thermal Green's function of the boundary operators. We also study the ideal system by placing it on curved spatial surfaces, specifically spherical surfaces. We compute the partition function and Green's function on spheres, squashed-sphere and hemispheres. Finally, we compute the large radius corrections to the partition function and Green's function by expanding in the large radius limit.

Jaynes-Cummings Hamiltonian provides the elemental description of a two-level system interacting with a photonic mode. In this Article, we derive an expression for the transmission response via a photonic signal that describes the hybridized states as separate photonic modes. As a result, we obtain the effective input/output couplings and the internal losses of each mode. These set the decoherence rate of the hybridized states, and provide a simple description of the strength of the response signal, that we call "visibility", and its linewidth. In particular, the result allows us to describe a situation where the coherence increases significantly while the signal remains strongly visible in the response.

When a high-energy particle, such as a $\gamma$-ray or muon, impacts the substrate of a superconducting qubit chip, large numbers of electron-hole pairs and phonons are created. The ensuing dynamics of the electrons and holes changes the local offset-charge environment for qubits near the impact site. The phonons that are produced have energy above the superconducting gap in the films that compose the qubits, leading to quasiparticle excitations above the superconducting ground state when the phonons impinge on the qubit electrodes. An elevated density of quasiparticles degrades qubit coherence, leading to errors in qubit arrays. Because these pair-breaking phonons spread throughout much of the chip, the errors can be correlated across a large portion of the array, posing a significant challenge for quantum error correction. In order to study the dynamics of $\gamma$-ray impacts on superconducting qubit arrays, we use a $\gamma$-ray source outside the dilution refrigerator to controllably irradiate our devices. By using charge-sensitive transmon qubits, we can measure both the offset-charge shifts and quasiparticle poisoning due to the $\gamma$ irradiation at different doses. We study correlations between offset-charge shifts and quasiparticle poisoning for different qubits in the array and compare this with numerical modeling of charge and phonon dynamics following a $\gamma$-ray impact. We thus characterize the poisoning footprint of these impacts and quantify the performance of structures for mitigating phonon-mediated quasiparticle poisoning.

Nonstabilizerness, also known as quantum magic, characterizes the beyond-Clifford operations needed to prepare a quantum state and constitutes an essential resource, alongside entanglement, for achieving quantum advantage. This work investigates how nonstabilizerness spreads under the dynamics of disordered quantum many-body systems. Using the $\ell$-bit model, a phenomenological model of many-body localization (MBL), we present an analytical description of the nonstabilizerness growth in MBL systems. We demonstrate that our analytical formulas describe the nonstabilizerness growth in strongly disordered quantum spin chains. Our findings establish a new facet of MBL phenomenology and identify the vital role of the disorder in slowing down the growth of the complexity of quantum states, important for our understanding of quantum advantage.

It is a folklore belief that metastable wells in low-temperature statistical mechanics models exhibit high-temperature behavior. We prove a rigorous version of this phenomenon in the setting of the exponential random graph model (ERGM) through the lens of concentration of measure. To do this, we first present a new general result deriving concentration inequalities in a metastable well from the metastable mixing of a Markov chain with the appropriate stationary distribution, extending a result of Chatterjee [Cha05] which is suited for more traditional forms of global mixing. We then apply this result to the supercritical (low-temperature) ERGM which was recently proven to exhibit metastable mixing by Bresler, Nagaraj, and Nichani [BNN24], and obtain a novel concentration inequality for Lipschitz observables of the supercritical ERGM conditioned on a large metastable well, answering a question posed by [BNN24]. This extends a result of Ganguly and Nam [GN24] from the subcritical (high-temperature) regime to a metastable well in the supercritical regime, and we are also able to extend the applications of their concentration inequality to these metastable wells. Namely, we obtain an upper bound on the Wasserstein distance between the ERGM conditioned on a metastable well and an appropriate Erd\H{o}s-R\'enyi model, as well as derive a central limit theorem for the count of edges in certain small subcollections of possible edges. Finally, to supplement the mathematical content of the article, we also discuss the results of what appears to be the first simulation study of a metastable well in the supercritical ERGM.

In this paper we explore the effects of instantaneous stochastic resetting on a planar slow-fast dynamical system of the form $\dot{x}=f(x)-y$ and $\dot{y}=\epsilon (x-y)$ with $0<\epsilon \ll 1$. We assume that only the fast variable $x(t)$ resets to its initial state $x_0$ at a random sequence of times generated from a Poisson process of rate $r$. Fixing the slow variable, we determine the parameterized probability density $p(x,t|y)$, which is the solution to a modified Liouville equation. We then show how for $r\gg \epsilon$ the slow dynamics can be approximated by the averaged equation $dy/d\tau=\E[x|y]-y$ where $\tau=\epsilon t$, $\E[x|y]=\int x p^*(x|y)dx$ and $p^*(x|y)=\lim_{t\rightarrow \infty}p(x,t|y)$. We illustrate the theory for $f(x)$ given by the cubic function of the FitzHugh-Nagumo equation. We find that the slow variable typically converges to an $r$-dependent fixed point $y^*$ that is a solution of the equation $y^*=\E[x|y^*]$. Finally, we numerically explore deviations from averaging theory when $r=O(\epsilon)$.