In generic classical and quantum many-body systems, where typically energy and particle number are the only conserved quantities, stationary states are described by thermal equilibrium. In contrast, integrable systems showcase an infinite hierarchy of conserved quantities that inhibits conventional thermalization, forcing relaxation to a Generalized Gibbs Ensemble (GGE), a concept first introduced in quantum many-body physics. In this study, we provide experimental evidence for the emergence of a GGE in a photonic system. By investigating partially coherent waves propagating in a normal dispersion optical fiber, governed by the one-dimensional defocusing nonlinear Schroedinger equation, we directly measure the density of states of the spectral parameter (rapidity) to confirm the time invariance of the full set of conserved charges. We also observe the relaxation of optical power statistics to the GGE's theoretical prediction, obtained using the experimentally measured density of states. These complementary measurements unambiguously establish the formation of a GGE in our photonic platform, highlighting its potential as a powerful tool for probing many-body integrability and bridging classical and quantum integrable systems.

The release properties of 4 targets (UC2, UC, UBC, UB2) were measured for 11 elements (Kr, Sr, Ru, Sn, Sb, Te, I, Cs, Ba, La, and Ce) using an off-line technique. The crystal packing fraction and the size of the studied element play a key role in the release process. However, physicochemical properties are also involved, notably melting and boiling points in vacuum and the minimal oxidation state. Principal component analysis was used to investigate the interrelationships between the physicochemical properties of fission products (from Fe to Dy) and the observed releases, thereby enabling predictions to be made about the release properties of the four crystallic configurations for elements that are inaccessible in off-line experiments.

Classical cellular automata represent a class of explicit discrete spacetime lattice models in which complex large-scale phenomena emerge from simple deterministic rules. With the goal to uncover different physically distinct classes of ergodic behavior, we perform a systematic study of three-state cellular automata (with a stable `vacuum' state and `particles' with $\pm$ charges). The classification is aided by the automata's different transformation properties under discrete symmetries: charge conjugation, spatial parity and time reversal. In particular, we propose a simple classification that distinguishes between types and levels of ergodic behavior in such system as quantified by the following observables: the mean return time, the number of conserved quantities, and the scaling of correlation functions. In each of the physically distinct classes, we present examples and discuss some of their phenomenology. This includes chaotic or ergodic dynamics, phase-space fragmentation, Ruelle-Pollicott resonances, existence of quasilocal charges, and anomalous transport with a variety of dynamical exponents.

Using the plane-wave pseudopotential method within the framework of density functional theory, Co$_2$MnAl (100), (110), and (111) surfaces with different atomic terminations have been studied in the context of some key spintronics properties, viz., surface energy, half-metallicity, magnetization, and magnetic anisotropy. The present study reveals that the MnAl-(100), Co-Al-(111), and Al-(111) surfaces exhibit negative surface energies over a wide range of chemical potentials, indicating their strong structural stability. The MnAl-(100), CoCoMnAl-(110), and Co-Mn-(111) surfaces maintain the nearly half-metallic nature like the bulk-Co$_2$MnAl, while this nearly half-metallic nature even improved for the Al-(111) surface. In contrast, the rest of the considered surfaces, CoCo-(100), Co-Al-(111) and Mn-(111) surfaces, display the strong metallic nature. Magnetization is enhanced for most surface configurations, except for Al-(111), where it decreases due to reduced moments of the exterior atoms. Regarding magnetic anisotropy, only the MnAl-(100) and Co-Mn-(111) surfaces exhibit the positive magneto-crystalline anisotropy of $\sim$0.23 and $\sim$0.33 mJ/m2, respectively. All these findings suggest that the Co-Mn-(111) and MnAl-(100) surfaces are quite appealing for spintronics applications, considering the structural stability, electronic properties, and magnetic anisotropy.

Antiferromagnets exhibiting the anomalous Hall effect represent a fascinating convergence of magnetism, topology, and electronic structure. Identifying antiferromagnets with large and tunable anomalous Hall effects is crucial for the development of spintronic applications. Here, we report a strain-tunable anomalous Hall plateau in CoNb$_3$S$_6$, which is a prime candidate for altermagnetism. The plateau emerges as a flat extended intermediate step of the anomalous Hall hysteresis loop with a controllable step height with temperature and strain. The remarkable tunability of the plateau position is in contrast with typical magnetic plateau associated with a field-induced metastable magnetic structure, but indicates the existence of a hidden phase transition that significantly alters the magnetic anisotropy energy without changing the magnetic order. The symmetry analysis of the strain tuning suggests that the hidden phase preserves the rotational symmetry of the ab-plane. Our results show the plateau reflects the phase coexistence during the hidden transition, and anomalous Hall resistivity of the plateau is thus non-volatile, enabling a novel four-state switching of the anomalous Hall effect.

Recently, there has been a growing interest in altermagnetism, a novel form of magnetism, characterized by unique spin-splitting even in the absence of both net magnetic moments and spin-orbit coupling. Despite numerous theoretical predictions, experimental evidence of such spin-splitting in real materials remains limited. In this study, we use angle-resolved photoemission spectroscopy (ARPES) combined with density functional theory (DFT) calculations to investigate the electronic band structure of the altermagnet candidate CoNb4Se8. This material features an ordered sublattice of intercalated Co atoms within NbSe2 layers. Magnetization and electrical resistivity measurements reveal the onset of antiferromagnetism below 168 K. Temperature dependent ARPES data, supported by DFT calculations, uncover spin split bands along the MGM high-symmetry direction. The observation of spin splitting in this high temperature altermagnet opens new avenues for exploring its electronic properties and potential applications in spintronic technologies.

Magnetic anisotropy in complex oxides often originates from the complex interplay of several factors, including crystal structure, spin-orbit coupling, and electronic interactions. Recent studies on Ru-substituted $La_{0.70}Sr_{0.30}MnO_3$ (Ru-LSMO) films demonstrate emerging magnetic and magneto-transport properties, where magnetic anisotropy plays a crucial role. However, the atomic origin and underlying mechanisms of the magnetic anisotropy of this material system remain elusive. This work sheds light on these aspects. Detailed element-specific X-ray magnetic dichroism analysis suggests that Ru single ion anisotropy governs the overall magnetic anisotropy. Furthermore, the magnetic property of Mn ions changes dramatically due to strong antiferromagnetic coupling between Ru and Mn ions. Our findings clarify the role of Ru single ion anisotropy behind magnetic anisotropy in Ru-LSMO, offering a promising avenue for designing advanced materials with tailored magnetic properties for next generation magnetic and spintronic technologies. As the Curie temperature of these materials is close to room temperature, such tunable magnetic anisotropy holds prospects for functional room-temperature magnetic devices.

We study the temporal, driven-dissipative dynamics of open photon Bose-Einstein condensates (BEC) in a dye-filled microcavity, taking the condensate amplitude and the noncondensed fluctuations into account on the same footing by means of a cumulant expansion within the Lindblad formalism. The fluctuations fundamentally alter the dynamics in that the BEC always dephases to zero for sufficiently long time. However, a ghost-attractor, although it is outside of the physically accessible configuration space, attracts the dynamics and leads to a plateau-like stabilization of the BEC for an exponentially long time, consistent with experiments. We also show that the photon BEC and the lasing state are separated by a true phase transition, since they are characterized by different fixed points. The ghost-attractor nonequilibrium stabilization mechanism is alternative to prethermalization and may possibly be realized on other dynamical platforms as well.

The principles behind the sharp, singular structures in a crumpled sheet are well understood. Here we discuss more general ways of exploiting such sharp structures to control the shape of a sheet by deforming or forcing it elsewhere. Often, the induced shape leads to further sharp structures -- ``sub-singularities". Though weaker and softer than the primary singularities, they nevertheless provide robust ways of shaping a sheet. In simple cases we understand the reason for these and their strength. This paper surveys a broad range of other sub-structure phenomena and reports recent progress in understanding some of them.

In this paper, the 60-year-old concept of long-range interaction in percolation problems introduced by Dalton, Domb, and Sykes, is reconsidered. With Monte Carlo simulation -- based on Newman-Ziff algorithm and finite-size scaling hypothesis -- we estimate 64 percolation thresholds for random site percolation problem on a square lattice with neighborhoods that contain sites from the 7th coordination zone. The percolation thresholds obtained range from 0.27013 (for the neighborhood that contains only sites from the 7th coordination zone) to 0.11535 (for the neighborhood that contains all sites from the 1st to the 7th coordination zone). Similarly to neighborhoods with smaller ranges, the power-law dependence of the percolation threshold on the effective coordination number with exponent close to -1/2 is observed. Finally, we empirically determine the limit of the percolation threshold on square lattices with complex neighborhoods. This limit scales with the inverse square of the mean radius of the neighborhood. The boundary of this limit is touched for threshold values associated with extended (compact) neighborhoods.

One of the greatest challenges when designing new technologies that make use of non-trivial quantum materials is the difficulty associated with predicting material-specific properties, such as critical temperature, gap parameter, etc. There is naturally a great amount of interest in these types of condensed matter systems because of their application to quantum sensing, quantum electronics, and quantum computation; however, they are exceedingly difficult to address from first principles because of the famous many-body problem. For this reason, a full electron-nuclear quantum calculation will likely remain completely out of reach for the foreseeable future. A practical alternative is provided by finite temperature, multi component density functional theory (MCDFT), which is a formally exact method of computing the equilibrium state energy of a many-body quantum system. In this work, we use this construction alongside a perturbative scheme to demonstrate that the phenomena Peierls effect and Kohn Anomaly are both natural features of the KS equations without additional structure needed. We find the temperature dependent ionic density for a simple 1D lattice which is then used to derive the ionic densities temperature dependent affect on the electronic band structure. This is accomplished by Fourier transforming the ionic density term found within this KS electronic equation. Using the Peierls effect phonon distortion gap openings in relation to the Fermi level, we then perturb the KS ionic equation with a conduction electron density, deriving the Kohn Anomaly. This provides a workable predictive strategy for interesting electro-phonon related material properties which could be extended to 2D and 3D real materials while retaining the otherwise complicated temperature dependence.

We use high-resolution chemical potential measurements to extract the entropy of monolayer and bilayer graphene in the quantum Hall regime via the Maxwell relation $\left.\frac{d\mu}{dT}\right|_N = -\left.\frac{dS}{dN}\right|_T$. Measuring the entropy from $T=300$K down to $T=200$mK, we identify the sequential emergence of quantum Hall ferromagnetism, fractional quantum Hall states (FQH), and various charge orders by comparing the measured entropy in different temperature regimes with theoretical models. At the lowest temperature of $T \approx 200$mK we perform a detailed study of the entropy near even-denominator fractional quantum Hall states in bilayer graphene, and comment on the possible topological origin of the observed excess entropy.

In this work, we show a connection between superstatistics and position-dependent mass (PDM) systems in the context of the canonical ensemble. The key point is to set the fluctuation distribution of the inverse temperature in terms od the system PDM. For PDMs associated to Tsallis and Kaniadakis nonextensive statistics, the pressure and entropy of the ideal gas result lower than the standard case but maintaining monotonic behavior. Gas of non-interacting harmonic oscillators provided with quadratic and exponential PDMs exhibit a behavior of standard ED harmonic oscillator gas and a linear specific heat respectively, the latter being consistent with Nernst's third law of thermodynamics. Thus, a combined PDM-superstatistics scenario offers an alternative way to study the effects of the inhomogeneities of PDM systems in their thermodynamics.

We study laser-induced ultrafast magnetization reversal in ferromagnetic spin valve by comparing the effect of a direct laser excitation and an ultrashort hot-electron pulse. A wedged Cu layer is grown on top of the spin valve in order to tune the energy transmission to the magnetic stack, for both optical and hot-electron pulses. We demonstrate single-pulse magnetization reversal of the free layer by a hot-electron pulse. The influence of laser fluence, Cu thickness ($t_{\mathrm{Cu}}$), and pulse duration is investigated in detail. These results suggest that free layer heating plays a significant role in magnetization reversal. This work contributes to the understanding of ultrafast magnetization reversal due to nonlocal heat and spin transport occurring under strongly out-of-equilibrium conditions.

Recent years have witnessed a great interest in orbital related electronics (also termed as orbitronics). In the current work, we present a first-principles density functional theory calculation on the orbital magnetic moments, intrinsic orbital Hall effect, and ordinary magnetoconductivity effects in rhombohedral graphene multilayers. Our calculations suggest a giant orbital moment that arises from inter-atomic cycloid motion, reaching over 30 muB under an intermediate gate voltage. This leads to a valley polarization under an external magnetic field, as observed in recent experiments [Nature 623, 41-47 (2023)]. In addition, the orbital-related transport feature exhibit significant responses that are potentially observed in experiments. We also suggest that under a periodic field driven (such as high frequency light field), the ungated graphene multilayers could host strong quantum anomalous and orbital Hall effects, engineered by the layer number. As the graphene multilayers are intrinsically nonmagnetic with negligible spin-orbit coupling, the orbital moments would not be entangled by spin-related signals. Thus, they serve as an ideal platform to conduct orbitronic measurements and utilization for next generation information read/write nanodevices.

Noncontacting and nondestructive control of geometric phase in conventional semiconductors plays a pivotal role in various applications. In the current work, we present a theoretical and computational investigation on terahertz (THz) light-induced phase transformation of conventional binary semiconducting compounds among different structures including rock-salt, zinc-blende, wurtzite, and hexagonal phases. Using MgS and MgSe as prototypical examples, we perform anharmonic phonon mediated calculations and reveal large contrasting lattice contributed dielectric susceptibility in the THz regime. We then construct a THz-induced phase diagram under intermediate temperature and reveal rock-salt to hexagonal and then wurtzite structure transformations with increasing light intensity. This does not require a high temperature environment as observed in traditional experiments. The low energy barrier suggests that the phase transition kinetics can be fast, and the stable room temperature phonon dispersions guarantee their non-volatile nature. Furthermore, we disclose the phononic hyperbolicity with strong anisotropic THz susceptibility components, which serves as a natural hyperbolic material with negative refractive index. Our work suggests the potential to realize metastable hidden phases using noninvasive THz irradiation, which expands the conventional pressure-temperature ($P-T$) phase diagram by adding light as an additional control factor.

Accelerated materials discovery is an urgent demand to drive advancements in fields such as energy conversion, storage, and catalysis. Property-directed generative design has emerged as a transformative approach for rapidly discovering new functional inorganic materials with multiple desired properties within vast and complex search spaces. However, this approach faces two primary challenges: data scarcity for functional properties and the multi-objective optimization required to balance competing tasks. Here, we present a multi-property-directed generative framework designed to overcome these limitations and enhance site symmetry-compliant crystal generation beyond P1 (translational) symmetry. By incorporating Wyckoff-position-based data augmentation and transfer learning, our framework effectively handles sparse and small functional datasets, enabling the generation of new stable materials simultaneously conditioned on targeted space group, band gap, and formation energy. Using this approach, we identified previously unknown thermodynamically and lattice-dynamically stable semiconductors in tetragonal, trigonal, and cubic systems, with bandgaps ranging from 0.13 to 2.20 eV, as validated by density functional theory (DFT) calculations. Additionally, we assessed their thermoelectric descriptors using DFT, indicating their potential suitability for thermoelectric applications. We believe our integrated framework represents a significant step forward in generative design of inorganic materials.

We present a comprehensive investigation of light-induced phase transitions and strain in two-dimensional NbOX$_{2}$ (X = Cl, Br, I) using first-principles calculations. In particular, we identify a light-induced ferroelectric-to-paraelectric phase transition in these 2D systems. Furthermore, we demonstrate the possibility of inducing an antiferroelectric-to-paraelectric transition under illumination. Additionally, we find that these 2D systems exhibit significant photostrictive behavior, adding a new functionality to their already notable optical properties. The ability to control and manipulate ferroelectric order in these nanoscale materials through external stimuli, such as light, holds considerable promise for the development of next-generation electronic and optoelectronic devices.

Critical points with emergent symmetry exhibit intriguing scaling properties induced by two divergent length scales, attracting extensive investigations recently. We study the driven critical dynamics in a three-dimensional $q$-state clock model, in which the ordered phase breaks the $Z_q$ discrete symmetry, while an emergent $U(1)$ symmetry appears at the critical point. By increasing the temperature at a finite velocity $v$ to traverse the critical point from the ordered phase, we uncover rich dynamic scaling properties beyond the celebrated Kibble-Zurek mechanism. Our findings reveal the existence of two finite-time scaling (FTS) regions, characterized by two driving-induced time scales $\zeta_d\propto v^{-z/r}$ and $\zeta_d'\propto v^{-z/r'}$, respectively. Here $z$ is the dynamic exponent, $r$ is the usual critical exponent of $v$, and $r'$ represents an additional critical exponent of $v$ associated with the dangerously irrelevant scaling variable. While the square of the order parameter $M^2$ obeys the usual FTS form, the angular order parameter $\phi_q$ shows remarkably distinct scaling behaviors controlled by both FTS regions. For small $v$, $\phi_q$ is dominated by the time scale $\zeta_d$, whereas for large $v$, $\phi_q$ is governed by the second time scale $\zeta_d'$. We verify the universality of these scaling properties in models with both isotropic and anisotropic couplings. Our theoretical insights provide a promising foundation for further experimental investigations in the hexagonal RMnO$_3$ (R=rare earth) materials.

Recent studies have shown some unusual nonlinear dispersion behaviors that are disconnected from the linear regime. However, existing analytical techniques, such as perturbation methods, fail to correctly capture these behaviors. Here we propose a general theoretical approach that converts the nonlinear wave equation to an equivalent linear eigenvalue problem, which directly gives the nonlinear dispersion relation and modal vectors. The theoretical approach is employed to 1D phononic chains and 2D hexagonal lattices with alternating softening and hardening nonlinearities, revealing amplitude-induced bandgap opening and closing phenomena. The theoretical results are validated via full-scale simulations with periodic boundary conditions, in which steady-state nonlinear plane wave responses are numerically obtained. Moreover, we leverage these nonlinear phenomena to achieve tunable frequency splitting and focusing effects. Thus, our work opens new paradigms for understanding nonlinear wave physics and for achieving novel wave control capabilities.

Final report for a Deutsche Forschungsgemeinschaft, Eigenestelle Grant, summarizing work mainly on uniaxial-pressure-dependent nuclear magnetic resonance (NMR) investigations of BaFe$_2$As$_2$. We have conducted systematic $^{75}$As NMR experiments in BaFe$_2$As$_2$ under in-situ controlled conditions of uniaxial pressure. We find that the electric field gradient (EFG), spin--lattice relaxation rate T$_1^{-1}$, spin--spin relaxation rate T$_2^{-1}$, and Knight shift $K$ at the As site are sensitive to applied uniaxial pressure. These properties allow us to locally probe the nematic susceptibility, as well as orbital and spin degrees of freedom. Our spectral measurements in the magnetic state provide no evidence for spin reorientation below the T$_N$ for both positive and negative applied uniaxial pressure up to the point of sample failure.

The topological characteristics of Bi and its alloys with Sb have fueled intense debate since the prediction of three-dimensional topological insulators. However, a definitive resolution has not been reached to date. Here, we provide theoretical evidence that surface relaxation conceals the underlying bulk topology of pure Bi. Using density functional theory calculations for thin Bi(111) films (up to 17 bilayers), we first demonstrate a substantial inter-bilayer expansion near the surface. Motivated by this finding, we extend our analysis to thick Bi(111) films (up to 250 bilayers) incorporating relaxation layers, within the framework of a relativistic empirical tight-binding model. Our results reveal that these relaxation layers topologically block the emergence of surface state and significantly suppress the one-particle spectrum of surface states, thereby obscuring the experimental identification of Bi's topological properties. This phenomenon, which we term "topological blocking", provides crucial insights into the long-standing difficulty of observing surface states of Bi(111) at the $\bar{M}$ point. Furthermore, it establishes a framework for understanding and predicting the topological behavior in systems where surface relaxation disrupts the bulk-edge correspondence.

Kagome magnets can combine non-trivial band topology and electron correlations, offering a versatile playground for various quantum phenomena. In this work we propose that kagome magnets with frustrated interlayer interactions can intrinsically support a self spin-valve effect, and experimentally confirm this in the kagome helimagnet TmMn$_6$Sn$_6$. Under a magnetic field perpendicular to the helical axis, using magnetic force microscopy we observed stripe domains that stack strictly along the helical axis, which we attribute to the stability loss of the kagome helimagnetic state. Such a domain pattern spontaneously mimics the artificial multilayered structure in traditional spin valves, which, combined with the high spin polarization, leads to a giant magnetoresistance (GMR) ratio over 160%. This discovery opens an avenue to realize inherent spin valves in a variety of quantum magnets, and can hold promise in future spintronics.

We develop a non-Lorentzian approach for quantum emitters (QE) resonantly coupled to localized surface plasmons (LSP) in metal-dielectric structures. Using the exact LSP Green function, we derive non-Lorentzian version of Maxwell-Bloch equations which describe LSP in terms of metal complex dielectric function rather than via Lorentzian resonances. For a single QE coupled to the LSP, we obtain an explicit expression for the system effective optical polarizability which, in the Lorentzian approximation, recovers the classical coupled oscillator (CO) model. We demonstrate that non-Lorentzian effects originating from the temporal dispersion of metal dielectric function affect dramatically the optical spectra as the system transitions to the strong coupling regime. Specifically, in contrast to Lorentzian models, the main spectral weight is shifted towards the lower energy polaritonic band, consistent with the experiment.

A new continuous model of shearable rod, subject to large elastic deformation, is derived from nonlinear homogenization of a one-dimensional periodic microstructured chain. As particular cases, the governing equations reduce to the Euler elastica and to the shearable elastica known as 'Engesser', that has been scarcely analysed so far. The microstructure that is homogenized is made up of elastic hinges and four-bar linkages, which may be realized in practice using origami joints. The equivalent continuous rod is governed by a Differential-Algebraic system of nonlinear Equations (DAE), containing an internal length ratio, and showing a surprisingly rich mechanical landscape, which involves a twin sequence of bifurcation loads, separated by a 'transition' mode. The latter occurs, for simply supported and cantilever rods in a 'bookshelf-like' mode and in a mode involving faulting (formation of a step in displacement), respectively. The postcritical response of the simply supported rod exhibits the emergence of folding, an infinite curvature occurring at a point of the rod axis, developing into a curvature jump at increasing load. Faulting and folding, excluded for both Euler and Reissner models and so far unknown in the rod theory, represent 'signatures' revealing the origami design of the microstructure. These two features are shown to be associated with bifurcations and, in particular folding, with a secondary bifurcation of the corresponding discrete chain when the number of elements is odd. Beside the intrinsic theoretical relevance to the field of structural mechanics, our results can be applied to various technological contexts involving highly compliant mechanisms, such as the achievement of objective trajectories with soft robot arms through folding and localized displacement of origami-inspired or multi-material mechanisms.

Inspired by Kitaev's real-space representation of Chern numbers, we develop a real-space formulation of the Berry phase for infinite lattices. While the well-known Resta formula for the Berry phase is defined under periodic boundary conditions for finite lattices, our approach constructs the Berry phase directly on an infinite lattice without requiring momentum-space discretization. We apply this method to several disordered models to examine its validity. Furthermore, we attempt to generalize the real-space representation to the quadrupole moment, drawing an analogy to the generalization of the Resta formula for the quadrupole moment.

Current-induced zero resistance (CIZR) in twisted trilayer graphene/WSe$_2$ has posed a theoretical challenge, as it goes beyond understanding of the existing theories of critical current and superconducting diode effect. In this Letter, we demonstrate that CIZR can be understood based on three-fold (near-)degenerate Fulde-Ferrell states, by studying a minimal tight-binding model on a triangular lattice with valley polarization and trigonal warping. We ellucidate that Fulde-Ferrell states are stabilized due to broken two-fold rotational symmetry, making an exception to the common belief that Larkin-Ovchinnikov states are stable in most cases. After establishing the thermodynamic phase diagram in electric current, we propose a scenario that predicts nonreciprocal and reciprocal CIZR in the presence of domains of different Fulde-Ferrell states. The triangular finite-momentum state is also predicted, unraveling another fascinating aspect of valley-polarized superconductors.

With the development of two-dimensional (2D) magnetic materials, magneto-optical Kerr effect (MOKE) is widely used to measure ferromagnetism in 2D systems. Although this effect is usually inactive in antiferromagnets (AFM), recent theoretical studies have demonstrated that the presence of MOKE relies on the symmetry of the system and antiferromagnets with noncollinear magnetic order can also induce a significant MOKE signal even without a net magnetization. However, this phenomenon is rarely studied in 2D systems due to a scarcity of appropriate materials hosting noncollinear AFM order. Here, based on first-principles calculations, we investigate the HfFeCl6 monolayer with noncollinear Y-AFM ground states, which simultaneously breaks the time-reversal (T) and time-inversion (TI) symmetry, activating the MOKE even though with zero net magnetic moment. In addition, four different MOKE spectra can be obtained in the four permutation states of spin chirality and crystal chirality. The MOKE spectra are switchable when reversing both crystal and spin chirality. Our study provides a material platform to explore the MOKE effect and can potentially be used for electrical readout of AFM states.

Recent years have seen a growing interest in the thermodynamic cost of dissipative structures formed by active particles. Given the strong finite-size effects of such systems, it is essential to develop efficient numerical approaches that discretize both space and time while preserving the original dynamics and thermodynamics of active particles in the continuum limit. To address this challenge, we propose two thermodynamically consistent kinetic Monte Carlo methods for active lattice gases, both of which correctly reproduce the continuum dynamics. One method follows the conventional Kawasaki dynamics, while the other incorporates an extra state-dependent prefactor in the transition rate to more accurately capture the self-propulsion velocity. We find that the error scales linearly with time step size and that the state-dependent prefactor improves accuracy at high P\'{e}clet numbers by a factor of $\mathrm{Pe}^2$. Our results are supported by rigorous proof of convergence as well as extensive simulations.

We investigate the role of atomic distortions in non-relativistic spin splitting in perovskite oxides with Pbnm symmetry. Using LaMnO3 as a representative material, we analyze its non-relativistic spin splitting through a combined phonon and multipolar analysis. Our study provides key insights into how structural distortions and magnetic ordering drive ferroically ordered magnetic multipoles, which, in turn, give rise to non-relativistic spin splitting. Based on these findings, we propose three strategies for engineering non-relativistic spin splitting: modifying the A-site cation size, strain engineering, and electric field control in superlattice structures. Our work establishes a framework for designing non-relativistic spin splitting in the Brillouin zone of oxide perovskites.

Anyons are quasiparticles with fractional statistics, bridging between fermions and bosons. We propose an experimental setup to measure the statistical angle of topological anyons emitted from a quantum point contact (QPC) source. The setup involves an droplet along a fractional quantum Hall liquid edge, formed by defining a droplet with two negatively biased gates. In the weak tunneling regime, we calculate the charge current, showing its time evolution depends solely on the anyons' statistical properties, with temperature and scaling dimension affecting only the constant prefactor. We compute the cross-correlation between the anyon current transmitted from the source and the current after the junction, providing a direct method to detect anyon braiding statistics.

We experimentally study the heterogeneity of strain in a granular medium subjected to oscillatory shear in a rotating drum. Two complementary methods are used. The first method relies on optical imaging and grain tracking, allowing us to compute some components of the strain tensor and their variance. The second method, Diffusive Acoustic Wave Spectroscopy (DAWS), provides the variance of strain components within the bulk. Our results show that strain is spatially heterogeneous, with fluctuations about ten times larger than the mean, primarily dominated by variability at the grain scale. We then analyze in detail the strain fluctuations occurring during the forward and backward branches of the shear cycles, as well as the plastic strain at the completion of each cycle. Both methods reveal that each shear cycle consists of two consecutive diffusive-like branches, and that the resulting plastic strain fluctuations grow linearly with shear. We propose a simple framework to rationalize these effects, suggesting that plastic strain fluctuations increase with the diffusion coefficient and decrease with the anticorrelation between forward and backward strain, which is enhanced in denser packings.

The persistent dynamics of active particles makes them explore extended portions of an obstacle's boundary during collisions. From impact to escape, the net applied forces depend on the curvature of the wall and increase in the presence of concave features. Here we systematically investigate the forces exerted by swimming bacteria on microfabricated structures, where the radii of curvature can be varied parametrically. We find that these micro-sails are propelled with a speed that scales linearly with curvature and is directed from concave to convex side along the axis of symmetry. By solving the collision problem for microswimmers with aligning torque interactions, we demonstrate that, unlike spherical active particles, curvature mainly affects cell orientation during sliding, leading to greater normal thrust on the concave side and an net applied thrust that scales linearly with curvature.

In this work, we demonstrate the voltage control of magnetic anisotropy in a strain-mediated Ni90Fe10/BaTiO3(001) heterostructure. In the pristine state of the heterostructure, the Magneto-Optical Kerr Effect measurements show a transcritical hysteresis loop for the Ni90Fe10 film, indicating a weak perpendicular anisotropy. This was further confirmed by X-ray Magnetic Circular Dichroism - Photoemission Electron Microscopy, revealing stripe domains in this film. X-ray diffraction analysis of the BaTiO3 substrate under varying electric fields was used to analyze the orientation of ferroelectric domains. These results indicated that BaTiO3 exhibits two distinct states depending on the applied electric field: one with domains aligned with the electric field and another with random domain orientation when the field is removed. After substrate poling, the Ni90Fe10 layer switches from weak perpendicular anisotropy to an in-plane uniaxial magnetic anisotropy, with the in-plane direction of anisotropy being controllable by 90{\deg} through an electric field. This effect is due to an efficient strain transfer from BaTiO3 to the Ni90Fe10 lattice, induced by ferroelectric polarization, as shown by XRD. Remarkably, this rotation of the magnetic anisotropy leads to an enhanced converse magnetoelectric coupling value of 1.43 {\mu}s/m, surpassing previously reported values for other BaTiO3-based heterostructures by an order of magnitude. These results emphasize the potential of Ni90Fe10 alloys for next-generation magnetoelectric devices.

In this paper, we propose an electronic refrigerator based on a ballistic Andreev interferometer that allows to reach a maximum cooling power per channel up to five orders of magnitude larger than that of the conventional normal metal-insulator-superconductor cooler. This effect is achieved by exploiting the destructive interference that occurs when the superconducting phase difference equals $\pi$. This results in a strongly suppressed charge current below the superconducting gap, while still allowing the extraction of excitations above the gap, leading to a cooler with enhanced performance. Interestingly, we find that such a large cooling power per channel enables the achievement of an electronic temperature close to the theoretical lower bound. Additionally, we derive an approximate expression for this bound in the regime of low bath temperatures. Finally, we propose potential implementations of the ballistic Andreev interferometer cooler using semiconductors, graphene, and topological insulators.

Lattice thermal conductivity ($\kappa_L$) is crucial for efficient thermal management in electronics and energy conversion technologies. Traditional methods for predicting \k{appa}L are often computationally expensive, limiting their scalability for large-scale material screening. Empirical models, such as the Slack model, offer faster alternatives but require time-consuming calculations for key parameters such as sound velocity and the Gruneisen parameter. This work presents a high-throughput framework, physical-informed kappa (PINK), which combines the predictive power of crystal graph convolutional neural networks (CGCNNs) with the physical interpretability of the Slack model to predict \k{appa}L directly from crystallographic information files (CIFs). Unlike previous approaches, PINK enables rapid, batch predictions by extracting material properties such as bulk and shear modulus from CIFs using a well-trained CGCNN model. These properties are then used to compute the necessary parameters for $\kappa_L$ calculation through a simplified physical formula. PINK was applied to a dataset of 377,221 stable materials, enabling the efficient identification of promising candidates with ultralow $\kappa_L$ values, such as Ag$_3$Te$_4$W and Ag$_3$Te$_4$Ta. The platform, accessible via a user-friendly interface, offers an unprecedented combination of speed, accuracy, and scalability, significantly accelerating material discovery for thermal management and energy conversion applications.

Aliovalent doping in an oxide material introduces modifications in the valence state of the host cation and often leads to tailoring the oxygen content in the lattice. Moreover, if the dopant cation is larger than the host cation, the lattice strain and disorder may be affected. Such changes are expected to modify the electronic clouds and lead to different ligand fields, which in turn should modify the bond lengths, and therefore phonons, electronic properties, transport properties, and charge storage properties. To understand such correlations an example is being investigated in this study by doping a larger Li+ ion in a NiO lattice. The effect on structure, phonons, electronic properties, and charge storage properties are investigated and correlated in a first-of-its-kind report. The charge storage properties are observed to improve with Li+ doping until 3% substitution and thereafter decrease due to the generation of Li+ interstitial in a 6% incorporated sample. The connection of oxygen vacancies and Ni3+ formation with Li+ incorporation is the backbone of this report.

We reanalyze the hydrodynamic theory of "flock" that is, polar ordered "dry" active fluids in two dimensions. For "Malthusian" flocks, in which birth and death cause the density to relax quickly, thereby eliminating density as a hydrodynamic variable, we are able to obtain two exact scaling laws relating the three scaling exponents characterizing the long-distance properties of these systems. We also show that it is highly plausible that such flocks display long-range order in two dimensions. In addition, we demonstrate that for "immortal" flocks, in which the number of flockers is conserved, the extra non-linearities allowed by the presence of an extra slow variable (number density) make it impossible to obtain any exact scaling relations between the exponents. We thereby demonstrate that several past published claims of exact exponents for Malthusian and immortal flocks are all incorrect.

We investigated the electronic structure, Fermi surface topology and the emergence of valley imbalance in rhombohedral trilayer graphene (RTG) induced by the topological proximity and the electric fields. We show that, a strong proximity strength isolates the unperturbed low energy bands at the charge neutrality and the isolated topological bands show metallic nature under the influence of applied electric fields. Our calculations indicate that valley-resolved metallic states with a finite Chern number $|C| =$3 can appear near charge neutrality for appropriate electric fields and second-nearest-neighbor strengths. The Fermi surface topology of these metallic bands greatly influenced by the applied electric fields and carrier doping. The valley imbalance lead to the dominant carriers of either $e^-$ or $h^+$ Fermi surface pockets and the choice of carriers is subjected to the direction of electric fields. The gate-tunable and carrier-induced valley imbalance in topologically proximated rhombohedral trilayer graphene may have potential applications toward the realization of superconductivity.

The Van Hove singularities (VHSs), where the electronic density of states diverges due to saddle points in the band structure, play a crucial role in enhancing electronic correlations and driving various instabilities. In particular, VHS-induced superconductivity has earned significant attention due to its potential to achieve high transition temperatures and its tendency to favor exotic pairing states beyond conventional electron-phonon mechanisms. Despite extensive research on VHS-driven superconductivity, the multi-orbital effect on such systems remains less explored. Motivated by recent experiments on several kagome metals under doping and pressure [Z.Zhang {\it et al.}, Phys.Rev.B {\bf 103}, 224513 (2021), Y.Sur {\it et al.}, Nat.Commun. {\bf 14}, 3899 (2023)], we explore the effects of multi-orbital physics and strong correlations induced by VHS in the kagome lattice, focusing on their impact on superconductivity. Using parquet renormalization group analysis, we uncover eight distinct superconducting instabilities, characterized by order parameters with mixed orbital degrees of freedom. Among these, we identify a parameter regime where $d$-wave-like orbital-singlet spin-triplet order parameters dominate as the leading instability. The degenerate spin-triplet states in this regime are capable of breaking time-reversal symmetry, which is a multi-orbital analogue of chiral spin-triplet superconductivity. These findings highlight the interplay between multi-orbital effects on superconductivity and can apply to the kagome metal systems such as $A$V$_3$Sb$_5$ ($A$ = K, Rb, Cs) family.

The kagome lattice has emerged as a fertile ground for exotic quantum phenomena, including superconductivity, charge density waves, and topologically nontrivial states. While AV3Sb5 (A = K, Rb, Cs) compounds have been extensively studied in this context, the broader AB3C5 family remains largely unexplored. In this work, we employ machine-learning-accelerated, high-throughput density functional theory calculations to systematically investigate the stability and electronic properties of kagome materials derived from atomic substitutions in the AV3Sb5 structure. We identify 36 promising candidates that are thermodynamically stable, with many more close to the convex hull. Stable compounds are not only found with a pnictogen (Sb or Bi) as the C atom but also with Au, Hg, Tl, and Ce. This diverse chemistry opens the way to tune the electronic properties of the compounds. In fact, many of these compounds exhibit Dirac points, Van Hove singularities, or flat bands close to the Fermi level. Our findings provide an array of compounds for experimental synthesis and further theoretical exploration of kagome superconductors beyond the already known systems.

We propose a model of a polycrystalline alloy combining the Potts model for grain orientations with a lattice-gas model for solute thermodynamics and diffusion. The alloy evolution with this model is implemented by kinetic Monte Carlo simulations with nonlinear transition barriers between the states. The model is applied to investigate the long-standing question of whether grain boundary (GB) segregation of an appropriate solute can drive the GB free energy to zero, creating a fully stabilized polycrystalline state with a finite grain size. The model reproduces stable polycrystalline states under certain conditions, provided the solute-solute interactions are repulsive. The structure minimizing the total free energy is not static. It exists in a state of dynamic equilibrium between the competing processes of grain growth and grain refinement. The alloy eliminates triple junctions by forming a set of smaller grains embedded into a larger matrix grain. It is predicted that, if a fully stabilized nanocrystalline state is implemented experimentally, it will look very different from the conventional (unstable) nanocrystalline materials.

Advanced theoretical investigations are crucial for understanding the structural growth mechanisms, optoelectronic properties, and photocatalytic activity of photoelectrodes for efficient photoelectrochemical water splitting. In this work, we conducted first-principles calculations aimed at designing $\alpha$-Fe2O3 photoelectrodes incorporating mono-dopants such as boron (B), yttrium (Y), and niobium (Nb), as well as co-dopants (B, Y) and (B, Nb) to enhance the performance of photoelectrochemical cells. We assessed the thermodynamic phase stability by calculating formation enthalpy ($E_f$) and examining material properties, including microstrain ($\mu_\epsilon$) and crystallite size ($D$). The mono-dopants, Y and Nb, and the co-dopants, (B, Y) and (B, Nb), exhibited negative $E_f$ values under the substitutional doping method, confirming their thermodynamic phase stability and suggesting their practical viability for experimental implementation. Notably, the values of $\mu_\epsilon$ and $D$ fell within the ranges observed experimentally for $\alpha$-Fe2O3, indicating their effectiveness in growth mechanisms. To gain a comprehensive understanding of the optoelectronic properties of doped $\alpha$-Fe2O3, we calculated the electronic band structure, density of states, atom's ionic charge, and optical absorption coefficient. This analysis allowed us to examine the improvements in the electronic charge characteristics and photon-electron interactions. B-doped $\alpha$-Fe2O3 led to the formation of impurity bands, which were mitigated by utilizing co-dopants (B, Y) and (B, Nb). The metal dopants, Y and Nb, significantly increased the charge carrier density, while the co-dopants, (B, Y) and (B, Nb), substantially enhanced light absorption in the visible spectrum.

The geometry of a physical system is intimately related to its spectral properties, a concept colloquially referred to as "hearing the shape of a drum". Three-dimensional topological insulator nanowires in a strong magnetic field $B$ generally host Dirac-type quantum Hall (QH) surface states. The surface itself is shaped by spatial variations of the wires' cross section, yielding a curved geometrical background, the "drum", with imprints in the corresponding QH spectra. We show that the latter are composed of two different classes. The first one is asymptotically insensitive to the surface shape, scaling as $B^{1/2}$, like regular planar QH states. Instead, the second has an asymptotic $B$-field dependence intimately related to the wire geometry. We further demonstrate that an (axial-symmetric) curved nanowire surface possesses a reciprocal partner surface, such that the respective QH spectra are dual to each other upon exchanging angular momentum and magnetic flux. Notably, a cone-shaped nanowire, and the Corbino geometry as its limiting case, has a reciprocal partner with a dual QH spectrum that is $B$-field independent, with corresponding non-magnetic QH-type states. We support our analytical findings by numerical results for $B$-field ranges and wire geometries within reach of current experiment.

This paper presents progress towards the large-scale manufacturability of piezo- and ferroelectric Al$_{1-x}$Sc$_x$N thin films with very high Sc content. Al$_{0.6}$Sc$_{0.4}$N layers were deposited by reactive sputtering from a 300 mm diameter Al$_{0.6}$Sc$_{0.4}$N target on standard 200 mm Si wafers with Pt bottom- and Mo top-electrodes. The deposited films were analyzed in depth with X-Ray diffraction (XRD), Reciprocal Space Mapping (RSM), Scanning electron microscopy (SEM) and Energy Dispersive X-Ray Spectroscopy (EDX) showing well oriented c-axis growth over the full wafer with slight variation in the film thickness and Sc content over the wafer radius. An overall low density of abnormally oriented grains (AOG) was found. Further wafer mapping for piezoelectric and dielectric properties showed a piezoelectric performance increase by 40 % in comparison to Al$_{0.7}$Sc$_{0.3}$N while only moderately increasing the permittivity and loss factor. Switching measurements revealed ferroelectric behavior of the film on all measured positions with an average remanent polarization of 88.36 uC/cm$^2$ and an average coercive field of 244 V/um. This successful demonstration opens new opportunities for MEMS applications with demands for high forces like microspeakers or quasi static micromirrors.

Biological machines harness targeted deformations that can be actuated by Brownian fluctuations. However, while synthetic micromachines can similarly leverage targeted deformations they are too stiff to be driven by thermal fluctuations and thus require strong forcing. Furthermore, systems that are able to change their conformation by thermal fluctuations do so uncontrollably or require external control. Here we leverage DNA-based sliding contacts to create colloidal pivots, rigid anisotropic objects that freely fluctuate around their pivot point, and use a hierarchical strategy to assemble these into Brownian metamaterials and machines with targeted deformation modes. We realize the archetypical rotating diamond and rotating triangle, or Kagome, geometries, and quantitatively show how thermal fluctuations drive their predicted auxetic deformations. Finally, we implement magnetic particles into the colloidal pivots to achieve an elementary Brownian machine with easily actuatable deformations that can harness Brownian fluctuations. Together, our work introduces a strategy for creating thermal mechanical metamaterials and leverages them for functional Brownian devices, paving the way to materialize flexible, actuatable structures for micro-robots, smart materials, and nano-medicine.

Shot noise measurements in quantum point contacts are a powerful tool to investigate charge transport in the integer and fractional quantum Hall regime, in particular to unveil the charge, quantum statistics and tunneling dynamics of edge excitations. In this letter, we describe shot noise measurements in a graphene quantum point contact in the quantum Hall regime. At large magnetic field, the competition between confinement and electronic interactions gives rise to a quantum dot located at the saddle point of the quantum point contact. We show that the presence of this quantum dot leads to a $50-100~\%$ increase in the shot noise, which we attribute to correlated charge tunneling. Our results highlight the role played by the electrostatic environment in those graphene devices.

Oxide glasses have the structure of disordered covalent networks that are accountable for their mechanical response. Identifying the topological phenomena of the elastic structural response, we statistically backpropagate local regions that have the highest susceptibility of rearrangement. Shear transformation zones in network glasses highly correlate with regions of the highest variance in their bond stretch distributions projected into the direction of macroscopic deformation. However, directional influence is significantly less essential than bond stretch variance, which shows that shear transformation zones in network glasses are mainly state-dependent. Exclusively depending on the local geometry of the initial material state, our indicators are physically informing and can be evaluated directly from images with insignificant computational effort.

We study an $\mathrm{SU}(3)$ invariant Fermi-Hubbard gas undergoing on-site three-body losses. The model presents eight independent strong symmetries preventing the complete depletion of the gas. By making use of a basis of semi-standard Young tableaux states, we reveal the presence of a rich phenomenology of stationary states. We classify the latter according to the irreducible representation of $\mathrm{SU}(3)$ to which they belong. We finally discuss the presence of three-particle stationary states that are not protected by the SU(3) symmetry.

The discovery of superconductivity with $T_c$ exceeding 40 K in La$_3$Ni$_2$O$_7$ and (La,Pr)$_{3}$Ni$_2$O$_7$ thin films at ambient pressure marks a significant breakthrough in nickelate superconductors. Using density functional theory (DFT), we propose the double-stacked two-orbital effective models for La$_3$Ni$_2$O$_7$ thin films, based on the Ni$-e_g$ orbitals. Our analysis reveals the presence of three electron pockets $\alpha,\alpha^{\prime},\beta$ and two hole pockets $\gamma,\gamma^{\prime}$ on the Fermi surface, where the additional pockets $\alpha^{\prime}$ and $\gamma^{\prime}$ emerge due to inter-stack interactions. Furthermore, we construct higher-energy models incorporating O-$p$ orbitals to facilitate further investigations. The spin susceptibility, calculated within the random phase approximation (RPA), indicates enhanced magnetic correlations primarily driven by nesting effects of the $\gamma$ pocket, which is predominantly contributed by the Ni$-d_{z^2}$ orbital. These models provide fundamental framework for further theoretical and experimental studies, offering critical insights into the superconducting mechanism of La$_3$Ni$_2$O$_7$ thin films.

Here, we report on controlling strain in graphene by trapping molecules at the graphene-substrate interface, leveraging molecular dipole moments. Spectroscopic and transport measurements show that strain correlates with the dipole moments of trapped molecules, with a dipole range of 1.5 D to 4.9 D resulting in a 50-fold increase in strain and a substantial rise in the residual carrier density. This has been possible by charge transfer between graphene and trapped molecules, altering the C=C bond length, and causing biaxial strain. First-principles density functional theory calculations confirm a consistent dependence of bending height on molecular dipole moments.

Superconducting electronics represents a promising technology, offering not only efficient integration with quantum computing systems, but also the potential for significant power reduction in high-performance computing. Nonetheless, the lack of superconducting memories better than conventional metal-oxide semiconductor (CMOS) memories represent a major obstacle towards the development of computing systems entirely based on superconducting electronics. In this work, we combine the emerging concept of gate-controlled supercurrent (GCS) with the well-established mechanism of charge-trapping memory to demonstrate a novel, highly scalable, voltage-controlled and non-volatile superconducting memory. GCS denotes the observation that the supercurrent in a superconducting constriction can be suppressed by applying a certain gate voltage (VG) to it. Our findings show that charge trapping within the gate dielectric, here sapphire, influences the voltage threshold needed to suppress the supercurrent. We demonstrate reliable reading and reversible writing of two distinct charge-trapping memory states, associated with different supercurrent values. Based on our memory device demonstrator, we discuss its integration into a NOT AND (NAND) gate layout, outlining the significant improvements offered by this novel memory concept over other existing NAND memory technologies.

Predicting crystal nucleation is among the most significant long--standing challenges in condensed matter. In the system most studied (hard sphere colloids), the comparison between experiments performed using static light scattering and computer simulations is woeful, with a discrepancy of over 10 orders of magnitude. The situation with other well-studied materials (such as water and sodium chloride) is no better. It has thus far proven impossible to access the regime of this discrepancy with particle-resolved techniques which might shed light on the origins of this discrepancy due to the relatively sluggish dynamics of the larger colloids required for confocal microscopy. Here we address this challenge with two developments. Our work is a marked improvement in the precision of mapping the state point of experiments to simulation. For this, we employed a combination of novel machine-learning methods for particle tracking and higher-order correlation functions. Our second innovation is to consider the free energy of \emph{pre--critical} nuclei which can be detected in the discrepancy regime. These are in agreement with computer simulation. This is the first time that such free energies have been directly compared between experiment and simulation in any material as far as we are aware. The agreement provides important validation of rare event sampling techniques which are used very widely in simulation, but which can seldom be directly compared with experiment.

We investigate the coarsening dynamics of a simplified version of the persistent voter model in which an agent can become a zealot -- i.e. resistent to change opinion -- at each step, based on interactions with its nearest neighbors. We show that such a model captures the main features of the original, non-Markovian, persistent voter model. We derive the governing equations for the one-point and two-point correlation functions. As these equations do not form a closed set, we employ approximate closure schemes, whose validity was confirmed through numerical simulations. Analytical solutions to these equations are obtained and well agree with the numerical results.

We study the dynamics of vortices in a Bose-Einstein condensate within a rotating four-site lattice which can be effectively described by a multimode model. Such a vortex dynamics develops along the low-density paths that separate the sites, and it is ruled by the phase differences between them. Hence, by appropriately selecting the initial conditions for on-site populations and phase differences, one can access distinct types of evolutions. We show that, by choosing equal populations in alternate sites, one can construct two-mode model Hamiltonians which allows us to model a large variety of associated vortex orbits. In particular, one can select the type of trajectory of the vortex and predict the creation and annihilation of vortex-antivortex pairs near the trap center. Estimates for the periods of closed vortex orbits and for the times that the vortices spend inside the lattice when dealing with open orbits, are obtained in terms of the two-mode models parameters and the rotation frequency only. We believe that the present study establishes a suitable platform to engineer different vortex dynamics.

Topological states of matter, first discovered in quantum systems, have opened new avenues for wave manipulation beyond the quantum realm. In elastic media, realizing these topological effects requires identifying lattices that support the corresponding topological bands. However, among the vast number of theoretically predicted topological states, only a small fraction has been physically realized. To close this gap, we present a new strategy capable of systematically and efficiently discovering metamaterials with any desired topological state. Our approach builds on topological quantum chemistry (TQC), which systematically classifies topological states by analyzing symmetry properties at selected wavevectors. Because this method condenses the topological character into mathematical information at a small set of wavevectors, it encodes a clear and computationally efficient objective for topology optimization algorithms. We demonstrate that, for certain lattice symmetries, this classification can be further reduced to intuitive morphological features of the phonon band structure. By incorporating these band morphology constraints into topology optimization algorithms and further fabricating obtained designs, we enable the automated discovery and physical realization of metamaterials with targeted topological properties. This methodology establishes a new paradigm for engineering topological elastic lattices on demand, addressing the bottleneck in material realization and paving the way for a comprehensive database of topological metamaterial configurations.

Solders with superconducting properties around $4\,{\rm K}$ are useful in low magnetic field environments for AC current leads or in electrical and mechanical bonds. Accurate knowledge of these properties are needed in high precision experiments. We have measured the electrical resistance of five commercially-available solders: 50\%Sn-50\%Pb, 60\%Sn-40\%Pb, 60\%Sn-40\%Pb-0.3\%Sb, 52\%In-48\%Sn, and 96.5\%Sn-3.5\%Ag, down to $2.3\,{\rm K}$ and in applied magnetic fields from 0 to 0.1$\,{\rm T}$. Their critical temperatures $T_c$ and critical fields $B_c$ were extracted in our analysis, taking into account the observed 90\%-to-10\% transition widths. Our best candidate for low-loss AC current leads in low fields is 50\%Sn-50\%Pb, which had zero-field $T_{c,0} = (7.1 \pm 0.3)\,{\rm K}$, and remained high to $T_c(B=0.1\,{\rm T}) = (6.9 \pm 0.3) \,{\rm K}$. We report $T_c$ and $B_c$ of 60\%Sn-40\%Pb-0.3\%Sb and $B_{c,0}$ of 96.5\%Sn-3.5\%Ag for the first time. Our $T_{c,0}= (3.31 \pm 0.04)\,{\rm K}$ for 96.5\%Sn-3.5\%Ag disagrees with a widely adopted value.

We reveal strong and weak inequalities relating two fundamental macroscopic quantum geometric quantities, the quantum distance and Berry phase, for closed paths in the Hilbert space of wavefunctions. We recount the role of quantum geometry in various quantum problems and show that our findings place new bounds on important physical quantities.

The current state of Quantum computing (QC) is extremely optimistic, and we are at a point where researchers have produced highly sophisticated quantum algorithms to address far reaching problems. However, it is equally apparent that the noisy quantum environment is a larger threat than many may realize. The noisy intermediate scale quantum (NISQ) era can be viewed as an inflection point for the enterprise of QC where decoherence could stagnate progress if left unaddressed. One tactic for handling decoherence is to address the problem from a hardware level by implementing topological materials into the design. In this work, we model several Josephson junctions that are modified by the presence of topological superconducting nanowires in between the host superconductors. Our primary result is a numerical calculation of the energy-phase relationship for topological nanowire junctions which are a key parameter of interest for the dynamics of qubit circuits. In addition to this, we report on the qualitative physical behavior of the bound states as a function of superconducting phase. These results can be used to further develop and inform the construction of more complicated systems, and it is hopeful that these types of designs could manifest as a fault tolerant qubit.

The growth of high-quality superconducting thin film on silicon substrates is essential for quantum computing, and low signal interconnects with industrial compatibility. Recently, the growth of $\alpha$-Ta (alpha-phase tantalum) thin films has gained attention over conventional superconductors like Nb and Al due to their high-density native oxide ($Ta_2O_5$), which offers excellent chemical resistance, superior dielectric properties, and mechanical robustness. The growth of $\alpha$-Ta thin films can be achieved through high-temperature/cryogenic growth, ultra-thin seed layers, or thick films (>300 nm). While high-temperature deposition produces high-quality films, it can cause thermal stress, silicide formation at the interface, and defects due to substrate-film mismatch. Room-temperature deposition minimizes these issues, benefiting heat-sensitive substrates and device fabrication. Low-temperature growth using amorphous (defective) seed layers such as TaN and TiN has shown promise for phase stabilization. However, nitrogen gas, used as a source of metallic nitride, can introduce defects and lead to the formation of amorphous seed layers. This study explores using crystalline seed layers to optimize $\alpha$-Ta thin films, demonstrating improved film quality, including reduced surface roughness, enhanced phase orientation, and higher transition temperatures compared to amorphous seed layers like metal nitrides. These advancements could interest the superconducting materials community for fabricating high-quality quantum devices.

Electromagnetic design relies on an accurate understanding of light-matter interactions, yet often overlooks electronic length scales. Under extreme confinement, this omission can lead to nonclassical effects, such as nonlocal response. Here, we use mid-infrared phonon-polaritons in hexagonal boron nitride (hBN) screened by monocrystalline gold flakes to push the limits of nanolight confinement unobstructed by nonlocal phenomena, even when the polariton phase velocity approaches the Fermi velocities of electrons in gold. We employ near-field imaging to probe polaritons in nanometre-thin crystals of hBN on gold and extract their complex propagation constant, observing effective indices exceeding 90. We further show the importance of sample characterisation by revealing a thin low-index interfacial layer naturally forming on monocrystalline gold. Our experiments address a fundamental limitation posed by nonlocal effects in van der Waals heterostructures and outline a pathway to bypass their impact in high-confinement regimes.

The bottom-up design of strongly interacting quantum materials with prescribed ground state properties is a highly nontrivial task, especially if only simple constituents with realistic two-body interactions are available on the microscopic level. Here we study two- and three-dimensional structures of two-level systems that interact via a simple blockade potential in the presence of a coherent coupling between the two states. For such strongly interacting quantum many-body systems, we introduce the concept of blockade graph automorphisms to construct symmetric blockade structures with strong quantum fluctuations that lead to equal-weight superpositions of tailored states. Drawing from these results, we design a quasi-two-dimensional periodic quantum system that - as we show rigorously - features a topological $\mathbb{Z}_2$ spin liquid as its ground state. Our construction is based on the implementation of a local symmetry on the microscopic level in a system with only two-body interactions.

Van der Waals (vdW) materials have garnered growing interest for use as nanophotonic building blocks that offer precise control over light-matter interaction at the nanoscale, such as optical metasurfaces hosting sharp quasi-bound states in the continuum resonances. However, traditional fabrication strategies often rely on lift-off processes, which inherently introduce imperfections in resonator shape and size distribution, ultimately limiting the resonance performance. Here, an optimized fabrication approach for vdW-metasurfaces is presented that implements inverse patterning of the etching mask, resulting in increased resonator quality solely limited by the resolution of the electron beam lithography resist and etching. Applying this inverse fabrication technique on hexagonal boron nitride (hBN), quality (Q) factors exceeding $10^3$ in the visible spectral range were demonstrated, significantly surpassing previous results shown by lift-off fabricated structures. Additionally, the platforms potential as a biosensor was displayed, achieving competitive sensitivity and figure of merit of 220 in a refractive index sensing experiment. The inverse technique was applied to create chiral metasurfaces from hBN, using a two-height resonator geometry to achieve up to 50 % transmittance selectivity. This inverse lithography technique paves the way towards high-performances vdW-devices with high-Q resonances, establishing hBN as a cornerstone for next-generation nanophotonic and optoelectronic devices.

By analyzing the physics of multi-photon absorption in superconducting nanowire single-photon detectors (SNSPDs), we identify physical components of jitter. From this, we formulate a quantitative physical model of the multi-photon detector response which combines local detection mechanism and local fluctuations (hotspot formation and intrinsic jitter) with thermoelectric dynamics of resistive domains. Our model provides an excellent description of the arrival-time histogram of a commercial SNSPD across several orders of magnitude, both in arrival-time probability and across mean photon number. This is achieved with just three fitting parameters: the scaling of the mean arrival time of voltage response pulses, as well as the Gaussian and exponential jitter components. Our findings have important implications for photon-number-resolving detector design, as well as applications requiring low jitter such as light detection and ranging (LIDAR).

A close relation has recently emerged between two of the most fundamental concepts in physics and mathematics: chaos and supersymmetry. In striking contrast to the semantics of the word 'chaos,' the true physical essence of this phenomenon now appears to be a spontaneous order associated with the breakdown of the topological supersymmetry (TS) hidden in all stochastic (partial) differential equations, i.e., in all systems from a broad domain ranging from cosmology to nanoscience. Among the low-hanging fruits of this new perspective, which can be called the supersymmetric theory of stochastic dynamics (STS), are theoretical explanations of 1/f noise and self-organized criticality. Central to STS is the physical meaning of TS breaking order parameter (OP). In this paper, we discuss that the OP is a field-theoretic embodiment of the 'butterfly effect' (BE) -- the infinitely long dynamical memory that is definitive of chaos. We stress that the formulation of the corresponding effective theory for the OP would mark the inception of the first consistent physical theory of the BE. Such a theory, potentially a valuable tool in solving chaos-related problems, would parallel the well-established and successful field theoretic descriptions of superconductivity, ferromagentism and other known orders arising from the spontaneous breakdown of various symmetries of nature.

The geometric properties of quantum states are crucial for understanding many physical phenomena in quantum mechanics, condensed matter physics, and optics. The central object describing these properties is the quantum geometric tensor, which unifies the Berry curvature and the quantum metric. In this work, we use the differential-geometric framework of vector bundles to analyze the properties of parameter-dependent quantum states and generalize the quantum geometric tensor to this setting. This construction is based on an arbitrary connection on a Hermitian vector bundle, which defines a notion of quantum state transport in parameter space, and a sub-bundle projector, which constrains the set of accessible quantum states. We show that the sub-bundle geometry is similar to that of submanifolds in Riemannian geometry and is described by a generalization of the Gauss-Codazzi-Mainardi equations. This leads to a novel definition of the quantum geometric tensor, which contains an additional curvature contribution. To illustrate our results, we describe the sub-bundle geometry arising in the semiclassical treatment of Dirac fields propagating in curved spacetime and show how the quantum geometric tensor, with its additional curvature contributions, is obtained in this case. As a concrete example, we consider Dirac fermions confined to a hyperbolic plane and demonstrate how spatial curvature influences the quantum geometry. This work sets the stage for further exploration of quantum systems in curved geometries, with applications in both high-energy physics and condensed matter systems.

A defining feature of quantum many-body systems is the exponential scaling of the Hilbert space with the number of degrees of freedom. This exponential complexity na\"ively renders a complete state characterization, for instance via the complete set of bipartite Renyi entropies for all disjoint regions, a challenging task. Recently, a compact way of storing subregions' purities by encoding them as amplitudes of a fictitious quantum wave function, known as entanglement feature, was proposed. Notably, the entanglement feature can be a simple object even for highly entangled quantum states. However the complexity and practical usage of the entanglement feature for general quantum states has not been explored. In this work, we demonstrate that the entanglement feature can be efficiently learned using only a polynomial amount of samples in the number of degrees of freedom through the so-called tensor cross interpolation (TCI) algorithm, assuming it is expressible as a finite bond dimension MPS. We benchmark this learning process on Haar and random MPS states, confirming analytic expectations. Applying the TCI algorithm to quantum eigenstates of various one dimensional quantum systems, we identify cases where eigenstates have entanglement feature learnable with TCI. We conclude with possible applications of the learned entanglement feature, such as quantifying the distance between different entanglement patterns and finding the optimal one-dimensional ordering of physical indices in a given state, highlighting the potential utility of the proposed purity interpolation method.

Quantum error mitigation (EM) is a family of hybrid quantum-classical methods for eliminating or reducing the effect of noise and decoherence on quantum algorithms run on quantum hardware, without applying quantum error correction (EC). While EM has many benefits compared to EC, specifically that it requires no (or little) qubit overhead, this benefit comes with a painful price: EM seems to necessitate an overhead in quantum run time which grows as a (mild) exponent. Accordingly, recent results show that EM alone cannot enable exponential quantum advantages (QAs), for an average variant of the expectation value estimation problem. These works raised concerns regarding the role of EM in the road map towards QAs. We aim to demystify the discussion and provide a clear picture of the role of EM in achieving QAs, both in the near and long term. We first propose a clear distinction between finite QA and asymptotic QA, which is crucial to the understanding of the question, and present the notion of circuit volume boost, which we claim is an adequate way to quantify the benefits of EM. Using these notions, we can argue straightforwardly that EM is expected to have a significant role in achieving QAs. Specifically, that EM is likely to be the first error reduction method for useful finite QAs, before EC; that the first such QAs are expected to be achieved using EM in the very near future; and that EM is expected to maintain its important role in quantum computation even when EC will be routinely used - for as long as high-quality qubits remain a scarce resource.

We demonstrate the emergence and control of Floquet states and topological bound states in the continuum (TBICs) in a two-dimensional colored quantum random walk (cQRW) on a square lattice. By introducing three internal degrees of freedom-termed "colors"-and leveraging SU(3) group representations, we realize dispersive TBICs and intrinsic Floquet dynamics without the need for external periodic driving. Through Chern number calculations, we identify three distinct topological bands, revealing color-induced band mixing as a key mechanism underlying the natural formation of Floquet states. The cQRW framework enables precise tuning of quasi-energy spectra, supporting the emergence of localized edge states in topological band gaps and dispersive TBICs embedded within the bulk of other bands. These TBICs exhibit tunable group velocity, controllable excitation across energy regimes, and robustness, providing theoretical validation for their existence in a first-order Floquet system. Our findings position cQRWs as a powerful platform for investigating and harnessing TBICs and Floquet states, with potential applications in quantum information and communication technologies.