We propose an exotic geometric M-theory dual for the weak coupling Type 0A string: compactification on a sub-Planckian $S^1\vee S^1$ (two circles connected at a point), where strong quantum effects lead to fields living on distinct resolutions of that space. Moreover we argue that tachyon condensation of the 0A theory corresponds to shrinking of one of the two circles leading to the IIA supersymmetric string. We use this and other dualities to provide an F-theoretic description of the axio-dilaton and the tachyonic field of Type 0B and argue for the existence of a strong coupling critical point of the potential using the resulting duality symmetry $\Gamma_0(2)\subset SL(2,\mathbb{Z})$. The existence of this critical point can also be argued using conventional M-theory dualities. If this critical point is unique it is an unstable dS vacuum. Using this we propose a strong coupling conformal fixed point for a non-supersymmetric gauge theory in four dimensions living on coincident $D3^+-D3^-$branes of 0B.

We compute the holographic Euclidean two-point function of scalar operators in a thermal state. We work directly using the Fourier series on the thermal circle. The Fourier series does not converge as a function, but instead converges as a distribution, consistent with QFT expectations. The result is manifestly periodic and consistent with analyticity in the strip $0<\mathfrak{Re}(\tau)<\beta$. Expanding in $\tau$ we obtain all OPE coefficients, including the double-trace sector. Thus our approach has an advantage compared to recent work where double-traces were bootstrapped from stress-tensor data. Bouncing singularities appear as non-perturbative sectors in the transseries for Fourier coefficients, but their transseries parameters are all zero in the case of the Euclidean correlator.

We continue our analysis of quantum corrections in the complex structure moduli space of four-dimensional Type IIB/F-theory compactifications with N=1 supersymmetry. We find that limits in the complex structure moduli space of F-theory generically induce a strong backreaction on other sectors of the theory, reflecting the non-factorisation of the field space in genuine $N=1$ theories at the quantum level. Our focus is on quantum corrections to the Kähler moduli in F-theory on Calabi-Yau fourfolds and proceeds in two independent ways: A detailed analysis of the worldsheet theory of candidate EFT strings for pure complex structure infinite distance limits reveals a mismatch with expectations based on the classical effective action and points to a quantum obstruction of the limit. Complementary to this, we confirm, in large classes of theories, the existence of significant complex structure dependent quantum corrections to the action of BPS instantons which at tree-level are governed by the Kähler moduli. As the quantum corrections become uncontrolled at large complex structure, they require a co-scaling of the Kähler moduli to maintain perturbative control. As a result, the naive, classical effective action does not provide an accurate description of pure large complex structure regimes. We comment on possible implications for string phenomenology, specifically with regard to model building and moduli stabilisation.

Quantum error-correcting codes provide a powerful framework for emergent spacetime, yet existing holographic code models describe only quantum fields on a fixed background: in exact erasure-correcting codes, the entropic area term is state independent and cannot capture gravitational backreaction. We argue that this limitation is intrinsic to exact subsystem recovery and that incorporating backreaction instead requires approximate quantum error correction. We introduce a Ryu-Takayanagi-like entropy decomposition for approximate subsystem erasure-correcting codes, defining bulk matter entropy via optimal recovery and a complementary proto-area entropy as the difference between boundary entropy and recoverable bulk entropy. For a broad class of skewed quantum codes obtained by small nonlocal perturbations of exact codes, the proto-area increases monotonically with bulk entropy, closely aligning with the behavior of quantum extremal surfaces. We identify the origin of this response as a form of tripartite non-local magic in the Choi state of the encoding map, which vanishes in stabilizer codes and controls the leading matter-geometry coupling in approximate subsystem erasure-correcting codes.

We show that the Dirac dressing of the fermion is equivalent to a shift of the gauge parameter. For every gauge, the gauge-dependent part is projected out of the self-energy. After renormalization, the physical mass is the same for every dressing. The non-locality, compositeness, and path dependence associated with the dressing are therefore not physical obstructions.

Recent work has highlighted the deep connection between quantum information and spacetime geometry. Bousso and Shahbazi-Moghaddam (Phys. Rev. Lett. 128, 231301 (2022)) proved that ``hyperentropic'' regions -- where entropy exceeds the area bound -- inevitably lead to singularity formation. In this work, we explore the converse implication: does the thermodynamic consistency of such singularities require them to be hidden? We answer in the affirmative, establishing a Quantum Weak Cosmic Censorship principle governed by Generalized Entropy. This provides a semiclassical mechanism for censorship which forbids naked singularities. Since Quantum Weak Cosmic Censorship is a semiclassical statement, it is more robust than the classical Weak Cosmic Censorship showing naked singularities are forbidden in nature even if quantum effects are taken into account.

We compute the one-loop QED $\beta$-function coefficient directly from heat kernel data of the twisted Spin$^c$ Dirac operator on $S^3 \times S^1$. Using $\zeta$-function regularization, the logarithmic scale dependence is encoded in the $a_4$ coefficient of the spectral expansion. The $F_{\mu\nu} F^{\mu\nu}$ term in $a_4$ yields exactly $\beta(e) = e^3/(12\pi^2)$, independent of $r$, $L$, or background, verifying spectral RG flow without flat-space propagators. The result is independent of the radii of $S^3$ and $S^1$ and of the choice of gauge background, providing a parameter-free consistency check that spectral data on compact manifolds encode renormalization group information. Beyond a mere verification of the coupling flow, this result serves as a non-trivial consistency check of the Spectral Action Principle in a curved background. It demonstrates that universal quantum corrections can be extracted purely from geometric spectral invariants, distinguishing this geometric spectral derivation from momentum-space propagator methods.

The Covariant Phase Space Formalism (CPSF) provides a robust framework for deriving symplectic structures and surface charges in diffeomorphism-invariant theories. By construction, the CPSF operates on two distinct manifolds: the spacetime and the Solution Phase Space (SPS). In this paper, we advance the formalism by establishing a strictly parallel geometric formulation for both manifolds. Within this framework, we systematically analyze diffeomorphisms and frame changes on both spaces. While spacetime diffeomorphisms have been extensively studied in the literature, transformations on the SPS have been largely overlooked; we rigorously define and investigate these as changes of slicing on SPS. We demonstrate that the standard Wald-Zoupas criterion for the integrability of surface charge variations is inherently slicing-dependent. To resolve this issue, we develop the Frobenius theorem on the SPS and use it to extends the Wald-Zoupas condition into an inherently slicing-independent criterion for integrability. The Frobenius theorem on the SPS also yields a rigorous and natural definition of fundamental geometric quantities on the solution space, specifically the SPS connection, torsion, and curvature. Furthermore, this geometric machinery naturally distinguishes between fundamentally different surface fluxes: "fake" fluxes are identified mathematically as pure gauge artifacts of the SPS connection, while "genuine" fluxes manifest as non-vanishing SPS torsion, which directly relates to the physical gravitational News tensor. Finally, we present a geometric formulation of the Liouville theorem on the SPS, offering a unified classification scheme for theories with and without propagating bulk degrees of freedom.

The electric Gauss law in 11D SuGra is famously non-linear, whence its flux quantization must be in nonabelian cohomology. We have previously shown that the minimal admissible choice is 4-Cohomotopy, which in the presence of magnetized M5-probes takes its relative twistorial form. Here we discuss how this situation is further refined in the presence of M-string probes on the M5-worldvolume. Based on the superspace formulation of 11D SuGra, we find the nested Bianchi identities by iterating the superembedding construction for super p-branes. The resulting probe brane hierarchy (M1 on magnetized M5 in 11D bulk) turns out to admit flux quantization in a doubly-relative form of twisted Cohomotopy, classified by the factorization of the quaternionic Hopf fibration through the twistor fibration. The further equivariant refinement of this cohomology theory reduces on A-type singularities to a form of relative 2-Cohomotopy which geometrically engineers Chern-insulator phases on $\mathrm{M5}\cap \mathrm{A}_n$, with the M-string playing the role of gapped nodal lines.

Spectra of standard 1d potentials (double-well, sin-Gordon etc) are given by trans-series in coupling, including (badly divergent) perturbative series (PS), and nonperturbative terms. All of them are badly defined (e.g. PS are badly divergent) but in sum supposed to be good. In this paper we discuss an example of a potential with specially defined couplings making PS completely absent. We calculate its nonperturbative vacuum energy and show that they are reproduced by the action of certain complex solutions to holomorphic Newton equation.

We construct a two-dimensional action on the celestial sphere that describes the infrared sector of Abelian gauge and gravitational theories in four dimensions. In particular, we use the holographic model to reproduce (1) antipodal matching conditions for the superphaserotation and supertranslation Goldstone modes in four dimensions, (2) leading soft photon and graviton theorems, and (3) infrared factorization of amplitudes with generic dressed $in$ and $out$ states. Using (3), we reproduce the infrared divergences that plague the standard undressed amplitudes, and show that amplitudes involving Faddeev-Kulish dressed states are infrared finite. As a corollary, we use our holographic model to construct an infinite class of dressed states that give rise to infrared finite scattering amplitudes.

We discuss the semi-classical quantisation of supersymmetric membranes in holographic geometries with asymptotic AdS$_4$ and AdS$_7$ boundary conditions. In AdS$_4$ geometries this quantisation prompts the need of ensemble changes when comparing bulk and boundary observables arising from such membranes. We also discuss how supersymmetric membranes localise to loci where the background Killing spinor turns chiral, circumventing the need of evaluating their zero-mode moduli integrals. Finally, we discuss a bulk analysis of an infinite tower of membrane instantons, or giant gravitons, in AdS$_7$ geometries, whose worldvolume dynamics effectively reduces to a quantum mechanical system. This allows us to test, in a holographic setting, the emergence proposal that perturbative supergravity data may be extracted from towers of membrane instantons.

We analyze loop-induced group-like symmetries in theories where fields are labeled by basis elements of a fusion algebra constructed from the conjugacy classes of finite groups. Although the fusion rules for conjugacy classes are in general violated at loop level, residual group-like symmetries, including both Abelian and non-Abelian ones, remain exact through a procedure referred to as ``groupification''. By examining various conjugacy classes of finite groups realized in heterotic string theory on non-Abelian orbifolds, we identify an approximate discrete symmetry that controls the magnitude of loop-induced couplings. As a result, most parameters appearing in non-invertible selection rules are natural in the sense of 't Hooft. Furthermore, we discuss anomalies of the groupification symmetry, which can impose additional constraints on models with non-invertible fusion rules.

BPS quivers are central to our understanding of BPS states in 4d $\mathcal{N}=2$ supersymmetric field theories and of D-branes at Calabi-Yau threefold singularities. The two subjects are deeply interrelated through geometric engineering in Type II string theory, where a CY$_3$ quiver, also known as a 5d BPS quiver, describes fractional branes at a threefold singularity ${\bf X}$. We study the Galois cover ${\skew{2}\tilde Q}\rightarrow Q$ of any BPS quiver $Q$ by a finite abelian group $\mathbb{G}$, leading to a covering quiver ${\skew{2}\tilde Q}$. The Galois cover is determined by a $\mathbb{G}$-grading of the arrows of the quiver $Q$, which can be understood as an orbifolding procedure. In particular, if $Q$ is a CY$_3$ quiver for ${\bf X}$, then the Galois cover $\skew{2}\tilde Q$ is the CY$_3$ quiver for the orbifold singularity ${\bf X}/\mathbb{G}$. We explore such Galois covering procedures in the language of supersymmetric quiver quantum mechanics, in terms of fixed loci under $\mathbb{G}$ actions on moduli spaces of quiver representations, and in terms of homomorphisms between the Kontsevich-Soibelman algebras of $Q$ and ${\skew{2}\tilde Q}$. Our main result is an explicit covering formula for the BPS invariants of 4d $\mathcal{N}=2$ field theories, wherein the rational BPS invariant $\bar{\Omega}^Q(\gamma)$ of $Q$ is expressed as a sum of BPS invariants of $\skew{2}\tilde Q$. We derive this formula in various special cases, which include the case when $\gamma$ is a primitive charge vector, the case of general charge vectors for quivers without loops, and the case of CY$_3$ quivers for some simple geometries such as the conifold or local del Pezzo surfaces. The general formula is presented as a conjecture that can be verified in many examples.

We explain why Calabi-Yau and complete elliptic integrals do not contribute to conservative observables at fifth post-Minkowskian order, despite appearing in intermediate steps. At even loop orders, conservative contributions are tied to terms proportional to the logarithm of the momentum transfer, which in dimensional regularization arise from singular regions. We show that in the classical limit, the integral classes responsible for Calabi-Yau and complete elliptic behavior are absent from the ultraviolet singular structures that generate the required logarithm. This perspective also suggests alternative strategies for analyzing the classical limit of multiloop integrals in the conservative sector at even loop orders.

We study holographic Krylov complexity in the Coulomb branch of ${\cal N}=4$ SYM. Adopting the proposal that the time derivative of the Krylov complexity is dual to the proper radial momentum of a massive particle, we investigate two probe geodesics within this geometry. For one of the radial trajectories we obtain exact analytic results, even when additional motion in the internal space is included. In cases where the geodesic avoids the interior curvature singularity, the Krylov complexity exhibits oscillatory behavior, with a frequency governed by the Coulomb scale and an amplitude determined by the UV cutoff, the Coulomb scale, and the angular momentum. This oscillatory pattern is lost, when the radial trajectory is approaching the singularity. Finally, we compare our holographic results with field-theoretic calculations, finding qualitative agreement.

Black shells, a kind of black hole mimickers, are identified thermodynamically as bulk duals of baryon operators in vector models, indicating that such objects are essential for the consistency of higher spin gravity theories. Thermal baryons, with a spectrum of a 2+1-dimensional relativistic Fermi gas, are found to be precursors of the deconfinement phase transition in vector models, condensing at a slightly lower temperature. The early condensation means that baryons are statistically important already in the phase with weakly interacting higher spin fields. Furthermore, the mysterious scale of the deconfinement transition in vector models is naturally interpreted as the Fermi energy scale in the gas.

We study the oscillon/$Q$-ball relation in an extended model with non-canonical kinematics. The model contains a single real scalar field whose kinetic term is enlarged to include a generalizing function. We approximate the real sector up to the third order in a book-keeping parameter. In this context, we implement the Renormalization Group Perturbation Expansion (RGPE), from which we conclude that the relation between oscillons and underlying $Q$-balls holds even in the presence of nontrivial kinematics. We apply our results to the study of three different effective cases. In all of them, our expressions mimic the numerical evolution of nonstandard oscillons with great accuracy, especially for small and moderate amplitudes. As the initial amplitude increases, the numerical profile develops a modulated behavior, and we use a two $Q$-balls solution to seed our analytical oscillon. We discuss how our non-canonical construction allows the existence of a well-behaved oscillon in connection to the simplest $\phi^2$-potential. This novel profile behaves in the same general way as the previous ones. So, we argue that they belong to the same universality class. Finally, we extend our analysis to consider those contributions up to the fifth order in the approximation expansion. We explore an exotic $\phi^6$-scenario, and conclude that the relation between generalized oscillons and underlying $Q$-balls now belongs to a different universality class.

Among various applications of the AdS/CFT correspondence in condensed matter physics of particular importance is the realization of the phase transition between the normal and superconducting phase in a holographic QFT. After seminal papers on holographic superconductors that introduced the basic setup, one of the main lines of development focused on capturing the Meissner effect with all the relevant parameters, which requires inclusion of an external magnetic field. Although a complete holographic description of a superconductor is still lacking, the basic elements of the gravitational systems dual to what can be most accurately characterized as a charged superfluid have been established. Using holographic setups for describing three- and four-dimensional superconductors, we investigate the effect of noncommutative twist deformation of bulk fields on the phase transition parameters, such as the critical magnetic field and condensate. In a wider context, our results represent a first systematic attempt to elucidate the role of noncommutative gauge field theory as part of the bulk description of condensed matter systems.

Bouncing geodesics have been used as valuable probes of black hole singularities. In the dual boundary theory, the presence of bouncing geodesics is encoded in the analytic structure of correlation functions. Thus, when their existence is related to the presence of a black hole singularity, this presents a practical holographic framework to analyse, diagnose, and classify spacetimes with curvature singularities. To make this intuition precise, we use the Hadamard theory of hyperbolic differential equations to prove that both bulk and boundary retarded propagators diverge whenever two points can be connected by a null geodesic. We clarify why this statement remains valid beyond the geodesic regime (for operators of any dimension) and examine how holographic renormalisation modifies the structure of the dual propagator. We also present a general characterisation of bouncing geodesics and the associated singularities in correlation functions for arbitrary spacetimes. Furthermore, we compare the analytic structure of the correlators in position and momentum space and discuss explicit examples. Finally, we demonstrate the validity and concrete limitations of the bouncing geodesic approach to the study of black hole singularities. In particular, we show an explicit example of a black hole in the self-dual linear axion model, which has a curvature singularity despite the absence of bouncing geodesics.

We show that the Lagrangian of a Nambu-Goto $p$-brane satisfies the identity $\mathcal{L}_{\rm [\it p \rm]}=T_{\rm [\it p \rm]}/(p+1)$, with $T_{\rm [\it p \rm]}$ denoting the trace of the corresponding energy-momentum tensor, independently of the properties of the gravitational field. While for $p=0$ this reduces to the standard $\mathcal{L}_{\rm [0]}=T_{\rm [0]}$ relation, which determines the on-shell Lagrangian of point particles and their fluids, more generally it depends explicitly on the $p$-brane dimensionality. We explore the implications of this Lagrangian identity for the dynamics of non-self-intersecting cosmic string loops in a homogeneous and isotropic universe within $f(R,\mathcal{L}_{\rm m})$ gravity, showing that, unlike in general relativity, the proper mass of a cosmic string loop may evolve over cosmological timescales regardless of its small size or tension. Finally, we extend the analysis to the more general case of closed $p$-branes in $(N+1)$-dimensional Friedmann-Lemaître-Robertson-Walker spacetimes.

Multi-field models of inflation typically assume that interactions between particles can be treated perturbatively. Strongly-coupled models provide an intriguing alternative and may offer novel inflationary phenomenology. We study the "unparticle" scenario, where the inflaton is weakly mixed with a strongly-coupled sector, specified by a (gapless) conformal field theory. For certain choices of conformal scaling dimension, $\Delta$, the exchange of unparticles leads to distinctive non-Gaussian features in the primordial curvature distribution, including bispectra with enhanced squeezed limits and oscillations close to the equilateral regime. Efficiently analyzing these models using Cosmic Microwave Background (CMB) data is a challenge since the shapes are non-factorizable in momenta and often highly degenerate with single-field self-interactions. Here, we overcome these limitations using a library of tools, including neural-network factorization schemes and optimal CMB estimators. Our pipeline condenses 161 non-separable templates into just 7 factorizable forms, with negligible loss of signal-to-noise. We apply the model to the \textit{Planck} data, asking two key questions: (1) can we detect unparticles? (2) can we distinguish them from single-field self-interactions? Across $1\leq \Delta\leq 9$, we find a maximal signal-to-noise of $1.2\sigma$, implying no evidence for new physics. We also place the first CMB constraints on the modified consistency-condition-satisfying orthogonal bispectrum with $f^{\rm orth^*}_{\rm NL} = -12\pm12$. While many unparticle models are degenerate with single-field shapes, values of $\Delta$ close to half-integers have very different shapes, offering an intriguing future discovery channel. The methods developed herein can be directly applied to other classes of templates, motivating the exploration of models beyond the standard weakly-coupled paradigm.

We present a perturbative closed-time-path (in-in) formulation of an optomechanical system in which a quantum field interacts with a moving mirror via radiation pressure. We derive the effective action governing the dynamics of the moving mirror, incorporating the full back-reaction of the cavity field. These effects are encoded in fluctuation and dissipation kernels, that we show satisfy fluctuation-dissipation relations, and whose spectral structure reveals a direct connection with the underlying physical mechanism responsible for the back-reaction, that is particle creation by the dynamical Casimir effect. By deriving the semiclassical equations of motion for the moving mirror, and computing the energy radiated into the field within the in-out formalism of quantum field theory, we verify the energy balance between the mechanical energy dissipated by the optical back-reaction forces acting on the mirror and the energy carried by the particles created in the field.

The quark--gluon plasma produced in relativistic heavy--ion collisions behaves as a nearly perfect fluid characterized by an exceptionally small shear viscosity to entropy density ratio. Understanding the microscopic origin of this small viscosity remains an important problem in the theory of strongly interacting matter. In this work we investigate the transport properties of a gluonic plasma in a non--Abelian gauge theory in which gluons acquire a gauge--invariant mass through a topological $B\wedge F$ interaction. Integrating out the antisymmetric tensor field generates an effective massive gluon propagator that modifies the infrared behaviour of gluon exchange processes. Using relativistic kinetic theory and the Boltzmann transport equation we compute the shear viscosity of the plasma and derive the corresponding transport cross section for gluon scattering. The presence of the topological gluon mass provides a natural infrared regulator for $t$--channel gluon exchange, removing the divergence that appears in perturbative QCD with massless gluons. We show that when the topological mass scale is comparable to the soft momentum scale of the plasma, $m\sim gT$, the resulting viscosity to entropy density ratio naturally falls in the range inferred from hydrodynamic analyses of heavy--ion collision experiments. These results suggest that topological mass generation may provide a simple microscopic mechanism contributing to the near--perfect fluidity of the quark--gluon plasma.

In this paper, we present a statistical model of spacetime trajectories based on a finite collection of paths organized into a branched manifold. For each configuration of the branched manifold, we define a Shannon entropy. Given the variational nature of both the action in physics and the entropy in statistical mechanics, we explore the hypothesis that the classical action is proportional to this entropy. Under this assumption, we derive a Wick-rotated version of the path integral that remains finite and exhibits both quantum interference at the microscopic level and classical determinism at the macroscopic scale. In effect, this version of the path integral differs from the standard one because it assigns weights of non-uniform magnitude to different paths. The model suggests that wave function collapse can be interpreted as a consequence of entropy maximization. Although still idealized, this framework provides a possible route toward unifying quantum and classical descriptions within a common finite-entropy structure.

We obtain exact charged AdS black hole solutions in Einstein Lambda gravity including the effects of Born Infeld nonlinear electrodynamics and Perfect Fluid Dark Matter. The influence of the PFDM and BI parameters on the event horizon is analyzed. We compute the conserved and thermodynamic quantities and verify that they satisfy the first law of thermodynamics. Thermal stability is studied in the canonical ensemble using the heat capacity and Helmholtz free energy showing how PFDM and BI parameters affect local and global stability regions. We further investigate the thermodynamics in the extended phase space by treating the cosmological constant as thermodynamic pressure obtaining consistent conserved quantities and confirming the first law. The Ehrenfest equations are analytically verified demonstrating that the critical behavior corresponds to a second order phase transition. Heat engines associated with these black holes are also constructed to examine how PFDM and BI parameters influence their efficiency. Finally we analyze the geodesic structure through timelike and null trajectories using the effective potential determining conditions for stable and unstable circular orbits the innermost stable circular orbit and the photon sphere. PFDM significantly modifies the orbital structure while BI corrections are weaker.

Unmodeled beyond Standard Model (BSM) physics in neutrino propagation can masquerade as parameter degeneracies in future precision measurements. Because the upcoming DUNE and T2HK experiments will operate at substantially different baselines, interpreting their data under the standard three-flavor framework provides a powerful diagnostic tool: any propagation BSM effect will inevitably manifest as an artificial tension between their extracted parameters. We demonstrate this principle using the complex non-standard interactions (NSI) currently favored to resolve the $\sim2\sigma$ tension between NO$\nu$A and T2K. If these NSI solutions are realized, the NSI-induced interference term $\propto\sin(\delta_{\rm CP}+\phi)$ systematically distorts the DUNE appearance rates, leading to a correlated misidentification of the atmospheric mixing octant and the CP phase $\delta_{\rm CP}$. Specifically, for $\varepsilon_{e\mu}$ ($\varepsilon_{e\tau}$) NSI, the DUNE fit shifts toward CP- conserving values (the opposite CP half-plane) along with a preference for the wrong octant. In contrast, the shorter-baseline T2HK experiment remains largely insensitive to this effect. The resulting $\sim3\sigma$ incompatibility between the DUNE and T2HK standard-fit results (after 6 years of data collection for each experiment) provides a robust experimental diagnostic for propagation NSI, illustrating how baseline complementarity is essential to uncover new physics in the precision era.

Understanding the dynamics of quantum correlations in many-body systems is a central problem in non-equilibrium quantum physics. We study the spread of mixed-state entanglement in a minimal model of quantum chaos, the kicked field Ising model. By combining the replica trick with the space-time duality of the model, we determine the exact spectrum of the partially transposed reduced density matrix. The resulting flat spectrum leads to exact relations between entanglement negativity, odd entropy and Rényi mutual information at early times. Numerical results further demonstrate that for equal tri-partitions and at late times, all entanglement measures saturate to the Haar-random values. In contrast, for unequal tri-partitions Rényi mutual information and negativity vanish at late times, implying that the corresponding reduced density matrix is factorizable. Extensive numerical simulations also show that the relation remains quantitatively valid for generic initial states, leading us to conjecture it for all initial states and all times.

In this work we derive a reduced one-fluid plasma model from the relativistic Vlasov--Boltzmann--Maxwell system using a moment hierarchy reduction combined with strong-guide-field anisotropic ordering. The unresolved higher-moment sector of the hierarchy is projected onto its dominant slow thermodynamic mode, producing a scalar regulator variable that represents a coarse-grained combination of charge imbalance, pressure anisotropy, and irreversible kinetic production channels. The resulting reduced state vector admits a GENERIC (General Equation for Non-Equilibrium Reversible--Irreversible Coupling) representation in which the reversible sector reproduces reduced electromagnetic field-line dynamics while the irreversible sector governs slow thermodynamic relaxation. Linearization yields a pair of electromagnetic eigenmodes together with an additional real thermodynamic eigenvalue. The fast modes recover the standard gyrotropic cold-plasma response, including familiar limits such as whistler dispersion, while the slow mode drives gradual drift of the effective electromagnetic spectrum and provides a reduced mechanism for variability in relativistic magnetized plasmas with slowly evolving macroscopic equilibrium. The previous 3-field model captured only the thermodynamic slow-mode sector, whereas the fully closed extended GENERIC model also contains the explicit reversible nonneutral charge degree of freedom, whose frozen-thermodynamic limit recovers the nonneutral whistler-Alfven equations as a strict subset. The model is formulated within the GENERIC framework, ensuring consistency with first-principles nonequilibrium thermodynamics.

In three spacetime dimensions, pure Einstein gravity admits no local propagating degrees of freedom, yet nontrivial gravitational backgrounds such as the BTZ black hole provide a natural arena to probe dynamical extensions of the theory. In quadratic $f(R)$ gravity the Ricci scalar becomes a propagating degree of freedom - the scalaron. We investigate how localized Maxwell-Higgs vortices excite this scalar mode in a static BTZ black-hole background. Working in the perturbative regime $\alpha \ll \ell^2$, the trace equation reduces to a massive Klein-Gordon equation for the curvature scalar sourced by the trace of the vortex energy-momentum tensor. Using the Sturm-Liouville structure of the radial operator, we construct the corresponding Green function and obtain the curvature profile generated by an arbitrary localized source. The induced excitation exhibits a universal asymptotic decay $R(r) \sim r^{-(1+\nu)}$, independent of the detailed vortex structure. The scalar excitation is linearly stable, carries finite energy, and produces parametrically suppressed backreaction, ensuring the smooth recovery of the Einstein limit. These results provide a concrete realization of how higher-curvature corrections activate the unique local gravitational degree of freedom in three dimensions and how localized sources excite this scalar mode in black-hole spacetimes.

We study the quasinormal spectrum of massless scalar fields propagating on a family of regular BTZ black holes arising from an infinite tower of dimensionally regularized Lovelock corrections. These geometries are asymptotically AdS, reduce to the standard BTZ solution in the limit $\ell \to 0$, and resolve the central singularity by introducing a smooth core controlled by the new length scale $\ell$. The scalar quasinormal modes are computed using both Leaver's continued-fraction method and the Horowitz-Hubeny power-series method; the two approaches agree to high accuracy across the parameter space. We find that the regularization preserves linear stability ($\omega_I < 0$) while qualitatively reshaping the spectrum: as $\ell$ increases, BTZ-like complex branches collide with the imaginary axis and undergo a hierarchy of bifurcations into multiple purely imaginary branches, leading to mode switching and a nontrivial reordering of overtones as functions of $\ell$ and the harmonic index $m$. Our results place regular BTZ black holes within the emerging family of bifurcating quasinormal spectra known from nearly extremal and asymptotically AdS black holes, and highlight these $(2+1)$-dimensional geometries as a controlled arena for exploring geometric mechanisms behind spectral branching and late-time ringdown in regular black hole spacetimes.

We investigate primordial non-Gaussianity in the Inflation without an Inflaton (IWI) framework, where scalar perturbations are generated at second order by primordial gravitational waves in Einstein gravity on an exact de Sitter (dS) background. Since scalar modes are produced nonlinearly from tensor modes, non-Gaussianity is an intrinsic prediction of the mechanism. We compute the corresponding scalar bispectrum, derive the relevant contribution to the three-point function of the scalar potential, and evaluate its shape numerically. We find that, unlike the scalar power spectrum, the bispectrum depends logarithmically on the ultraviolet cutoff set by the end of inflation, indicating a structural difference between the two- and three-point statistics in this scenario. Its shape is enhanced toward squeezed configurations, but its amplitude becomes strongly suppressed once the scalar power spectrum is normalized to the observed value. The resulting non-Gaussianity at CMB scales is therefore negligibly small, well below present observational sensitivity.

We study the plausibility of a holographic dark energy (HDE) model using the form of horizon entropy proposed by Viaggiu in 2014. This form of entropy is a generalization of the usual Bekenstein-Hawking entropy, having an extra term arising due to the dynamical nature of horizons in an expanding universe. We examine this new HDE model in the context of a flat Friedmann-Lemaître-Robertson-Walker universe filled with two cosmic fluids -- dark matter in the form of dust and holographic dark energy generated by Viaggiu entropy. We consider the Hubble horizon and the future event horizon as characteristic length scales and study the evolution of the Universe within these frameworks. Our analysis reveals some intriguing findings that include a possible cosmic doomsday scenario in the future, and certain observations are in striking contrast to other HDE models studied in the literature.

We present a pedagogical and self contained account of the functional formulation of non-Abelian gauge theories, aimed at the construction of a process independent effective charge for Yang--Mills theory. Starting from the path integral quantization of gauge fields, we review gauge fixing and the emergence of Faddeev--Popov ghosts, illustrating how gauge invariance is preserved at the quantum level through Becchi--Rouet--Stora--Tyutin (BRST) symmetry. We then develop the BRST and anti-BRST formalisms and show how their simultaneous implementation leads to powerful functional identities that severely constrain the ghost and gluon sectors. Background field gauges are introduced as a natural framework in which these symmetries manifest themselves through Abelian like Ward identities, allowing for a transparent separation between quantum and background degrees of freedom. This structure makes it possible to define renormalization group invariant combinations of Green functions that generalize the QED effective charge to the non-Abelian case. The resulting effective charge is shown to be unique, gauge invariant, and process independent, providing a unified description of the theory from the ultraviolet down to the infrared. The interplay between functional identities, Dyson--Schwinger equations, and lattice results is discussed in detail, highlighting how dynamical mass generation and infrared saturation naturally emerge within this framework.

We test the cosmological viability of the Viaggiu holographic dark energy (VHDE) model by using late-time observational data. In particular, we place constraints on the free parameters of the model using Type Ia supernovae from the PantheonPlus, Union3.0, and DES-Dovekie catalogues, the Cosmic Chronometers, and the Baryon Acoustic Oscillations from the DESI DR2. Our analysis suggests that the VHDE model fits the observational data better or similar to the $\Lambda$CDM for all dataset combinations considered. The value obtained for $H_0$ is similar to the $\Lambda$CDM, while the current matter density parameter is constrained around $\Omega_{m0}\simeq 0.24$, smaller to that obtained by the $\Lambda$CDM. Moreover, the parameter introduced by the VHDE is found to have a mean value within the range $\frac{\pi}{3} \delta^2 \sim 0.27-0.33$. Finally, we used Akaike's Information Criterion (AIC) and Bayesian evidence to test the VHDE model against the $\Lambda$CDM scenario. The AIC demonstrates that the two models are statistically indistinguishable, while Bayesian evidence reveals that the data have a mild preference for the $\Lambda$CDM model for most of the dataset combinations considered. Nevertheless, the VHDE model remains consistent with current late-time cosmological observations and offers a feasible mechanism for describing the late-time accelerating scenario.

This work presents a detailed account of the Feynman integrals required for the three-loop hadronic vacuum polarization calculation performed in arXiv:2510.12885. We explain how to compute each of the three-loop integrals, and outline the mathematical framework underlying their evaluation. This culminates in a practical numerical implementation that enables fast and accurate evaluation of these integrals for arbitrary complex values of the photon virtuality.

We develop a Bohmian analysis of a two-dimensional ghost Hamiltonian and its mapping to the degenerate Pais-Uhlenbeck model. Using Gaussian wavepackets, we derive the corresponding guidance equations, the centre and width evolution, and the quantum potential. We use these quantities to characterise bounded, quasi-semiclassical, spiral, and runaway regimes. The Bohmian trajectories provide a direct dynamical diagnostic of coherence, packet deformation, and quantum-classical separation. We then compare a bi-Hamiltonian pair consisting of the ghost Hamiltonian and a classically equivalent alternative formulation. While the two descriptions produce identical classical trajectories, they lead to different Bohmian trajectories and different quantum potentials evaluated along those trajectories. This demonstrates that classical equivalence need not extend to Bohmian quantum dynamics and identifies a concrete quantum ambiguity in the degenerate higher-derivative system.

The large-distance development of a sandwich gravitational wave, consistent with Carroll symmetry, provides us with a surprisingly good analytic approximation of the motion of particles in a wave with Pöschl-Teller profile. The role of the 2nd solution of the Stern-Liouville equation is highlighted. Similar results hold for Gaussian profiles.

This paper explores the application of geometric algebra to Galilean spacetime and its physical implications. We introduce the Galilean Spacetime Algebra (GSTA), a five-dimensional conformal geometric algebra (CGA) generated by a specific metric, and demonstrate its utility in representing special Galilean transformations, rotations, and boosts. The general form of special Galilean transformations within the GSTA is derived, demonstrating their preservation. While the tensor formulation of Galilean electromagnetism is well-established, our work offers a fresh insight by deriving it from a geometric algebra perspective, utilizing the GSTA, and demonstrates how it seamlessly reduces to the familiar Maxwell equations in the non-relativistic limit. A significant aspect of this research is the introduction of Galilean spinors as elements of the minimal left ideals of the GSTA. We illustrate how these spinors can be utilized to construct the Lévy-Leblond equation for a free electron, along with its corresponding matrix representation. Furthermore, we establish a connection between the GSTA and the four-component dual numbers introduced by Majernik, suggesting pathways for developing a covariant formulation of Newtonian gravity. This work not only clarifies the geometric interpretation of Galilean symmetries but also opens avenues for future research in non-relativistic physics, highlighting the advantages of using CGA in this context.

We examine the physical significance of torsion co-cycles in the cohomology of a projective Calabi-Yau three-fold for the (2,2) superconformal field theory (SCFT) associated to the non-linear sigma model with such a manifold as a target space. There are two independent torsion subgroups in the cohomology. While one is associated to an orbifold construction of the SCFT, the other encodes the possibility of turning on a topologically non-trivial flat gerbe for the NS-NS B-field. Inclusion of these data enriches mirror symmetry by providing a refinement of the familiar structures and points to a generalization of the duality symmetry, where the topology of the flat gerbe enters on the same footing as the topology of the underlying manifold.

The recent developments in the study of topological multi-boundary entanglement in the context of 3d Chern-Simons theory (with gauge group $G$ and level $k$) suggest a strong interplay between entanglement measures and number theory. The purpose of this note is twofold. First, we introduce a $q$-deformed version of the Witten zeta function using the Chern-Simons theory at level $k$. We analyze the large $k$ limit of this function and show that it converges to an integer multiple of the classical Witten zeta function of $G$, where the integer multiple is precisely the order of the center of the group. This analysis provides an alternative way to compute the classical zeta functions, and we present some examples. Next, we study the quantum state associated with the $S^3$ complement of torus links of type $T_{p,p}$ and show that we can write the Rényi entropies at finite $k$ in terms of $q$-deformed Witten zeta functions. Using our first result, we obtain the $k \to \infty$ limit of the Rényi entropies and find that the entropies converge to finite values, which can be written in terms of the classical Witten zeta functions evaluated at positive integers. Since Witten zeta functions naturally appear in the symplectic volumes of moduli spaces of flat connections on Riemann surfaces, we give a geometric interpretation of the $k \to \infty$ limit of the Rényi and entanglement entropies in terms of these volumes. The results of this paper reveal an intriguing connection between topological entanglement, number-theoretic structures arising from Witten zeta functions, and the geometry of moduli spaces.

A longstanding conjecture in $\phi^4_4$ theory is that primitive graphs dominate the beta function asymptotically at large loop order in the minimal-subtraction scheme. Here we investigate this issue by exploiting additional combinatorial structure coming from an extension to vectors with $O(N)$ symmetry. For the 0-dimensional case, we calculate the $N$-dependent generating function of primitive graphs and its asymptotics, including arbitrarily many subleading corrections. We find that the leading asymptotic growth rate becomes visible only above $\approx 25$ loops, while data at lower order is suggestive of a wrong asymptotics. Our results also yield the symmetry-factor weighted sum of 3-connected cubic graphs, and the exact asymptotics of Martin invariants. For individual Feynman graphs, we give bounds on their degree in $N$ depending on their coradical degree, and construct the primitive graphs of highest degree explicitly. We calculate the 4D primitive beta function numerically up to 17 loops, and find its behaviour to be qualitatively similar to the 0D case. The locations of zeros quickly approach their large-loop asymptotics at negative integer $N$, while the growth rate of the beta function differs from the asymptotic prediction even at 17 loops.

We present a unified free field realization of the Ding-Iohara algebra at arbitrary levels, which satisfies a generalized form of the Serre relations. This realization, constructed using six free boson fields, arises from a specialized factorization of the structure function in the defining relations of the algebra. Based on this construction, we then develop intertwining operators for the Ding-Iohara algebra.

We develop a covariant Lagrangian formulation for a time reversal symmetry broken, minimally relativistic three dimensional Weyl superconductor that preserves continuous chiral invariance in the chiral limit. Within this framework, the FFLO pairing spontaneously breaks the axial $U(1)_A$ symmetry, giving rise to distinct collective excitations. Using the Nambu Jona Lasinio approach, we identify a pseudo scalar Nambu Goldstone mode (This mode is absent for conventional BCS internode pairing) that acquires a small mass under explicit chiral symmetry breaking and couples to gauge fields through the axial anomaly, closely analogous to the neutral pion decay in QCD. Although this anomaly induced decay is strongly suppressed in the bulk by the Meissner effect, it may occur via surface electromagnetic fields. Our analysis also predicts additional vector and axial vector collective modes associated with the broken $U(1)_A$ symmetry, providing a unified description of collective excitations in Weyl superconductors and their correspondence to mesonic modes in QCD.

We construct the $Z_{N}$ symmetry extended fusion ring of bulk and chiral theories and the corresponding modular partition functions with nonanomalous subgroup $Z_{n}(\subset Z_{N})$. The chiral fusion ring provides fundamental data for $Z_{N}$- graded symmetry topological field theories and also provides algebraic data for smeared boundary conformal field theories, which describe the zero modes of the extended models. For more general multicomponent or coupled systems, we also obtain a new series of extended theories. By applying the folding trick, their partition functions correspond to charged or gapped domain walls or massless renormalization group flows preserving quotient group structures.

In this work, we have performed a detailed holographic analysis of the stochastic dynamics of a heavy particle propagating through a strongly coupled plasma moving with a constant velocity along a fixed spatial direction. To model this scenario within the framework of the AdS/CFT correspondence, we consider a boosted AdS black brane geometry in the bulk. The boost corresponds to the uniform motion of the plasma on the boundary field theory side. The presence of this boost introduces a preferred direction, leading to an anisotropic environment in which the behavior of the Brownian particle differs depending on its direction of motion. Consequently, we examine two distinct cases, namely,Brownian motion parallel to the direction of the boost and motion perpendicular to it. In this work we have computed the diffusion coefficient for both along the boost and perpendicular to the boost directions. We have obtained the diffusion coefficient by following the two different approaches in both the cases. These complementary approaches yield consistent results, thereby reinforcing the reliability of the computations carried out. Additionally, we verify the fluctuation-dissipation theorem within this anisotropic setup, confirming its validity in both longitudinal and transverse to the direction of boost. Our findings provide deeper insight into the non-equilibrium transport properties of strongly coupled plasma and further elucidate the holographic description of Brownian motion in anisotropic backgrounds. Finally, we proceed to holographically compute the Butterfly velocity by using the entanglement wedge subregion duality and express the diffusion coefficients in terms of the chaotic observables.

It was recently established that the paradigmatic Gross--Neveu model with $N$ copies of two-dimensional Dirac fermions features an $\mathrm{SO}(2N)$ symmetry if certain interactions are suppressed. This becomes evident when the theory is rewritten in terms of $2N$ copies of two-dimensional Majorana fermions. Mean-field theory for the $\mathrm{SO}(2N)$ model predicts, besides the chiral Ising transition at $g_{c1}$, a second critical point $g_{c2}$ where $\mathrm{SO}(2N)$ is broken down to $\mathrm{SO}(N)\times\mathrm{SO}(N)$. A subsequent Wilsonian renormalization group analysis directly in $d=3$ supports its existence in a generalized theory, where $N_f$ copies of the $4N$-component Majorana fermions are introduced. This allows to track the evolution of a (i) quantum anomalous Hall Gross--Neveu--Ising, (ii) symmetric-tensor, and (iii) adjoint-nematic fixed point separately. However, it turns out that (ii) and (iii) lose their criticality when approaching $N_f = 1$, suggesting that the transition is first order. In this work, we approach the problem from the lower-critical dimension of two. We construct a Fierz-complete renormalizable Lagrangian, compute the leading order $\beta$ functions, fermion anomalous dimension, as well as the order parameter anomalous dimensions, and resolve the three universality classes corresponding to (i)--(iii). Before becoming equal to the Gaussian fixed point at $N_f = 1$, (ii) remains critical for all values of $N_f > N_{f,c}^{\mathrm{ST}}(N) \approx 0.56 + 1.48 N +\mathcal{O}(\epsilon)$, which compares well with the estimate of previous studies. We further find that (iii) becomes equal to (i) when approaching $N_f = 1$. An instability is, however, only present in the susceptibility corresponding to the Gross--Neveu--Ising order parameter.

In this paper we analyze a generalized "single-trace $T\bar T$" deformation, defined by a TsT transformation, of the fibered $I$-brane solution from \cite{Nunez2023}. We use the Penrose limit to understand it, and we consider both the TsT followed by the Penrose limit, as well as the Penrose limit followed by TsT. We describe the spin chains obtained in field theory. In the first case we find that, indeed, the TsT transformation preserves solvability in a simple way, as in the standard $T\bar T$ case. In the second case, we have several options, but none is simple enough to be conclusive, however, one case gives us an asymptotically free and IR nontrivial field theory sector, and another a new parallelizable pp wave.

The dual formulations of an infinite tower of tree-level soft theorems in asymptotically flat spacetimes for scattering amplitudes in the standard energy-momentum basis and for correlators of a 2D celestial conformal field theory imply a correspondence between the celestial operator product expansion (OPE) and the higher spin charge bracket. We apply such correspondence to provide first a prescription to solve the double-soft limit ambiguity in the mixed-helicity sector of celestial OPEs. Furthermore, demanding the charge OPE/bracket correspondence to remain valid when operators are shadow transformed, we construct an algorithm to compute shadow celestial OPEs. We first test the algorithm by recovering results in the previous literature involving the celestial energy-momentum tensor; we then apply it to both gravity and Yang-Mills theory and generalize the OPE derivation to arbitrary spins.

We report on the existence of a hydrodynamic attractor in the Mueller-Israel-Stewart framework of a fluid living in the novel geometry discovered recently by Grozdanov. This geometry, corresponding to a hyperbolic slicing of dS$_3\times\mathbb{R}$, complements previous analyses of attractors in Bjorken (flat slicing) and Gubser (spherical slicing) flows. The fluid behaves like a sharply localized droplet propagating rapidly along the lightcone. Typical solutions approach the hydrodynamic attractor rapidly at late times despite a Knudsen number exceeding unity, suggesting that the inverse Reynolds number captures hydrodynamization more faithfully since the shear stress vanishes at late times. This is in stark contrast to Gubser flow, which has both the Knudsen and inverse Reynolds number becoming small for intermediate times. We close with a comparison to Weyl-transformed Bjorken flow and discuss possible phenomenological applications.

We investigate the relationship between the functional renormalization group (RG) and the dual holography framework in the path integral formulation, highlighting how each can be understood as a manifestation of the other. Rather than employing the conventional functional RG formalism, we consider a functional RG equation for the probability distribution function, where the RG flow is governed by a Fokker-Planck-type equation. The central idea is to reformulate the solution of Fokker-Planck type functional RG equation in a path integral representation. Within the semiclassical approximation, this leads to a Hamilton-Jacobi equation for an effective renormalized on-shell action. We then examine our framework for an Einstein-Hilbert action coupled to a scalar field. Applying standard techniques, we derive a corresponding functional RG equation for the distribution function, where the dual holographic path integral serves as its formal solution. By synthesizing these two perspectives, we propose a generalized dual holography framework in which the RG flow is explicitly incorporated into the bulk effective action. This generalization naturally introduces RG $\beta$-functions and reveals that the RG flow of the distribution function is essentially identical to that of the functional RG equation.

The textbook N=1 supergravity has an F-term potential depending on a superpotential $W(z_i)$ and a Kahler potential $K(z^i, \bar z^{\bar i})$, with the scalar potential $V(z^i, \bar z^{\bar i})=e^K (|DW|^2 - 3 |W|^2)$. In this approach, it is not always easy to find the potential $V(z^i, \bar z^{\bar i})$ with the required properties. We show that in supergravity with a nilpotent superfield and with any Kahler potential $K(z^i, \bar z^{\bar i} )$ one can obtain any desired potential $V(z^i, \bar z^{\bar i})$ by a proper choice of the Kahler metric of the nilpotent superfield. This construction is particularly suitable for cosmological and particle physics applications, which may require maximal freedom in the choice of kinetic terms and scalar potentials.

We study $1/12$-BPS and $1/16$-BPS cohomologies and the fortuitous mechanism in ABJM theory. We first establish the existence of fortuitous states in the $N=1$ theory, where the theory is abelian and trace relations are extreme. We then provide explicit constructions of fortuitous states at $N=2$. We find fortuitous states both at weak coupling, in direct parallel to what has been done in $\mathcal{N}=4$ SYM, but we also find additional fortuitous states at $k=2$, which is in the strongly coupled regime. The extra fortuitous states that appear at $k=2$ are in non-trivial monopole sectors. A striking distinction from $\mathcal{N}=4$ SYM is that the fortuitous states appear at much smaller quantum numbers, making them easier to find. Along the way, we formulate a non-renormalization conjecture for cohomologies in ABJM.

Using supersymmetric localization, we show that the partition function of four-dimensional superconformal gauge theories - computed as a trace over BPS states without the insertion of $(-1)^F$ - is perturbatively protected and piecewise independent of the gauge coupling. We derive a matrix-integral representation of this observable at $g_{\text{YM}}=0$ for generic four-dimensional superconformal gauge theories. For $U(N)$ maximally supersymmetric Yang-Mills theory we study such a matrix integral and show that, even at finite $N$, it localizes to ensembles of superconformal indices near its essential singularities. The latter asymptotic localization projects out any potential discontinuity of the perturbatively protected partition function from zero to strong coupling and explains why single microcanonical indices reproduce the growth of the total number of BPS states in co-dimension one regions of large charges, up to large oscillations due to the insertion of $(-1)^F$. To compute quantum corrections to entropy at finite $N$ and small charges, the correct observable is the perturbatively protected partition function, which by definition is a positive quantity. We propose and test an improvement of the Cardy-like method that allows us to identify and compute perturbatively exact expressions for the leading large-$N$ on-shell action of eigenvalue configurations that we call orbifold, dressed orbifold, and eigenvalue-instanton saddles. These are also saddle points of large-charge expansions at finite $N$. We test the conclusions obtained from such large-charge saddle-point analysis at $N=2$ using explicit Cauchy-residue evaluation.

Conserved currents of relativistic spin fluids derived from microscopic models are known to violate local thermodynamic relations. We present a systematic analysis of pseudo-gauge improvements in ideal spin hydrodynamics and identify a family of pseudo-gauges where standard thermodynamic relations are satisfied. We quantify pseudo-gauge ambiguities in the spin equation of state and derive universal thermodynamic relations that apply to conserved currents in any pseudo-gauge. As an application, we extract the thermodynamic variables and equations of state for free Dirac fermions and scalar fields.

This work investigates a modified theory of gravity where the Einstein-Hilbert action, including a cosmological constant, is non-minimally coupled to a Yang-Mills field via an \(R^3 F_{\mu \alpha}^{(a)} F^{(a)\mu \alpha}\) interaction term. We treat this coupling as the leading higher-derivative correction in a low-energy effective field theory (EFT) deformation of the standard Einstein-Yang-Mills theory. We derive a black brane solution for this model, accurate to the first order in the EFT coupling parameter \(q_2\), and specify the regime of validity \(\frac{|q_2|}{L^6} \ll 1\). Using gauge/gravity duality techniques, we then compute two key holographic transport coefficients: the color non-abelian direct current (DC) conductivity and the ratio of shear viscosity to entropy density. Our analysis reveals that both transport coefficients are modified by the non-minimal coupling, with the conductivity bound violated for positive \(q_2\) and the Kovtun-Son-Starinets (KSS) bound for shear viscosity violated for negative \(q_2\). The results are interpreted within the EFT framework, and possible constraints on the sign of \(q_2\) from stability and causality are discussed. In the limit where the non-minimal coupling vanishes, our results consistently reduce to those of the standard Yang-Mills Schwarzschild Anti-de Sitter (AdS) black brane.

We construct new families of type-IIB supergravity solutions by employing TsT transformations on the ten-dimensional geometry that arises after the uplift of the five-dimensional soliton solution of Anabalón, Nastase, and Oyarzo. In particular, we identify two marginal and two dipole deformations of the uplifted geometry. We then analyse a plethora of holographic observables -- including Wilson loops, `t~Hooft loops, Page charges, entanglement entropy, and central charge -- and compare their behaviour across the different deformed backgrounds.

No-boundary instantons and Euclidean "wineglass" wormholes have both been proposed as providing suitable initial conditions for the current expanding phase of our universe, and in particular for providing conditions that are favorable to an inflationary phase. These finite action solutions have generally been regarded as unrelated, and enacting different scenarios - in one case the creation of spacetime from nothing, and in the other up-tunneling from a Euclidean Anti-de Sitter vacuum. By studying explicit solutions of both axionic and magnetic wineglass wormholes, we find that in the zero-charge limit the throat of the wormholes pinches off, leaving a no-boundary instanton that disconnects from the asymptotic Anti-de Sitter region. Thus wormholes and no-boundary instantons are part of a common family of Euclidean solutions. Along the way, we resolve the long-known puzzle that the action of wineglass wormholes can become negative. Moreover, small-charge wormholes lead to a longer inflationary phase than large-charge solutions, while no-boundary instantons dominate the probability distribution overall.

We consider the Euclidean vacuum for linearized gravity on the global de Sitter space, obtained from the Euclidean Green's function on the 4-sphere. We use the notion of Calderón projectors to recover a quantum state for the Lorentzian theory on de Sitter space. We show that while the state is gauge invariant and Hadamard, it is not positive on the whole of the phase space. We show however that a suitable modification at low energies yields a well-defined Hadamard state on global de Sitter space.

We investigate relativistic wavepacket dynamics for an electron tunneling through a potential barrier employing space-time resolved solutions to relativistic quantum field theory (QFT) equations. We prove by linking the QFT property of micro-causality to the wavepacket behavior that the tunneling dynamics is fully causal, precluding instantaneous or superluminal effects that have recently been reported in the literature. We illustrate these results by performing numerical computations for an electron tunneling through a potential barrier for standard tunneling as well for Klein tunneling. In all cases (Klein tunneling \ or regular tunneling across a standard or a supercritical potential) the transmitted wavepacket remains in the causal envelope of the propagator, even when its average position lies ahead of the average position of the corresponding freely propagated wavepacket.

One of the remarkable differences between renormalizable quantum gravity with four-derivative action and its superrenormalizable polynomial generalizations is that the latter admit a more sophisticated particle mass spectrum. Already in the simplest superrenormalizable case, the theory has a six-derivative Lagrangian, admitting either a real or complex spectrum of masses. In the case of a real spectrum, there are the graviton, massive unphysical ghosts, and normal particles with masses exceeding the ones of the ghosts. It is also possible to have pairs of complex conjugate massive ghost-like particles. We show that in both cases, these theories do not admit a Källén-Lehmann representation and do not satisfy the positivity criterium of consistency in terms of the fields associated to those particles. In the main part of the work, using a relatively simple Euclidean scalar toy model, we show that the theory with complex spectrum forms bound states confining unphysical massive excitations into a normal composite particle. Finally, we discuss the cosmological implications of such a ghost confinement.

We consider 4D $SU(N)$ gauge theories coupled to gravity in the Causal Dynamical Triangulations (CDT) approach, focusing on the topological classification of the gauge path integral over fixed triangulations. We discretize the topological charge and, after checking the emergence of topology and the continuum scaling on flat triangulations, we show that topology emerges on thermalized triangulations only in the so-called $C$-phase of CDT, thus enforcing the link between such phase and semiclassical spacetime. We also provide a tool to visualize the topological structures.

When the maximal isometry group of a four-dimensional spacetime acts simply transitively, such a Ricci-flat metric is uniquely determined to be the Petrov solution. This isometry group is almost abelian; that is, its Lie algebra contains an abelian ideal of codimension one. In this paper, we study Lorentzian left-invariant metrics on almost abelian Lie groups of dimension four or higher. In particular, we construct a Ricci-flat but non-flat metric that generalizes the Petrov solution to arbitrarily high dimensions. The generalized solution is geodesically complete and admits closed timelike curves.

We investigate gravitational waves with an arbitrary potential within the framework of linearized Horndeski theory. We show that the minimum of the potential can play the role of an effective cosmological constant in this theory, which is usually neglected in previous studies of this subject. We first determine the background geometry in this setup by solving the weak field scalar and tensorial equations of linearized Horndeski theory. The solutions of linearized weak-field wave equations, in an appropriate gauge, are then obtained perturbatively to study the propagation and interactions of gravitational waves in this background. We compare our results with different realizations of the cosmological constant in Horndeski theory to compare the role of an arbitrary scalar potential with those of vacuum energy density and a linear potential. The results show that the background curvature arising from the minimum of the scalar potential effectively mimics a cosmological constant, producing distinct redshifts in the frequency and wave number that distinguish the tensor waves from massive scalar ones. We also find that the way the cosmological constant is introduced directly influences the speed and polarization of the scalar wave.

We present a comprehensive analysis of inflationary models in light of projected sensitivities from forthcoming CMB and gravitational wave experiments, incorporating data from recent ACT DR6, DESI DR2, CMB-S4, LiteBIRD, and SPHEREx. Focusing on precise predictions in the $(n_s, \alpha_s, \beta_s)$ parameter space, we evaluate a broad class of inflationary scenarios -- including canonical single-field models, non-minimally coupled theories, and string-inspired constructions such as Starobinsky, Higgs, Hilltop, $\alpha$-attractors, and D-brane models. Our results show that next-generation observations will sharply constrain the scale dependence of the scalar power spectrum, elevating $\alpha_s$ and $\beta_s$ as key discriminants between large-field and small-field dynamics. Strikingly, several widely studied models -- such as quartic Hilltop inflation and specific DBI variants -- are forecast to be excluded at high significance. We further demonstrate that the combined measurement of $\beta_s$ and the field excursion $\Delta\phi$ offers a novel diagnostic of kinetic structure and UV sensitivity. These findings underscore the power of upcoming precision cosmology to probe the microphysical origin of inflation and decisively test broad classes of theoretical models.

The experimental search for the pion -- proposed in 1935 by Hideki Yukawa as the force carrier of the strong nucleon-nucleon interaction -- was rewarded in 1947 when in cosmic ray photographic emulsion data a charged particle was identified with the proper mass of about 300 times the electron mass, completed three years later by the discovery of the neutral pion. Since then, accelerator-driven pion and meson (photo-)production on the nucleon and the associated production of new baryons have become the key elements for ground-breaking discoveries in numerous areas of particle and nuclear physics, from fundamental symmetries and their breaking to low-energy QCD dynamics, laying also foundations for modern elementary particle physics and the Standard Model. This article is an overview of eight decades of experimental and theoretical meson production physics, from isospin to charm and beyond, forming our understanding of hadrons and their interactions.

We investigate the impact of one-loop radiative corrections in a non-supersymmetric model of hybrid inflation with a chaotic (polynomial-like) potential,$V(\phi) = V_0 + \lambda_p \phi^p$, in the light of the latest constraints from \textit{Planck} and \textit{Atacama Cosmology Telescope} (ACT) observations. Here, $V_0$ denotes the energy scale of inflation, and $\lambda_p$ is a coupling associated with the polynomial term of power $p$. These corrections can naturally arise from couplings of the inflaton to other matter fields, which also facilitate the reheating process. At the tree level, the predictions of such models for the scalar spectral index $n_s$ and the tensor-to-scalar ratio $r$ typically lie outside the current observational bounds. However, incorporating one-loop radiative corrections modifies the potential to, \[ V(\phi) = V_0 + \lambda_p \phi^p + A \phi^4 \ln (\phi/ \mu), \] where $A$ characterizes the strength of the inflaton's coupling to other fields, and \(\mu\) is an appropriate renormalization scale. This radiatively corrected potential can reconcile the model with the combined \textit{Planck}+ACT data over a suitable range of parameter space explored in this work. In particular, radiative corrections from fermionic loops ($A < 0$) suppress the tensor-to-scalar ratio $r$, while simultaneously yielding a red-tilted spectrum with $n_s < 1$, even for sub-Planckian field excursions. This brings the prediction in line with current observations, while still allowing for potentially detectable signatures of primordial gravitational waves. Furthermore, the inflaton's couplings enable successful reheating and naturally accommodate non-thermal leptogenesis, providing a unified framework for inflation and baryogenesis.

In this work, we employ the Tannaka-Krein reconstruction to compute the quantum double $\mathcal D(\mathcal G)$ of a finite 2-group $\mathcal G$ as a Hopf monoidal category. We also construct a 3+1D lattice model from the Dijkgraaf-Witten TQFT functor for the 2-group $\mathcal G$, generalizing Kitaev's 2+1D quantum double model. Notably, the string-like local operators in this lattice model are shown to form $\mathcal D(\mathcal G)$. Specializing to $\mathcal G = \mathbb{Z}_2$, we demonstrate that the topological defects in the 3+1D toric code model are modules over $\mathcal D(\mathbb{Z}_2)$.

We explore the maximum mass limit of strange stars in quadratic curvature gravity with the non-minimal matter coupling. The characteristic parameters of the quadratic curvature coupling and the non-minimal matter coupling imply the contributions from higher-order curvature terms and the coupling between matter and geometry, respectively. We demonstrate, explicitly, that the conservation of energy-momentum tensor can be modified and in the case of negligible non-minimal matter coupling, the formalism of general relativity is recovered. By deriving the Tolman-Oppenheimer-Volkoff equations from the gravitational field equations and applying the MIT bag model equation of state, we obtain the corresponding mass-radius relationships for strange stars. Although the MIT bag model represents a simplified phenomenological equation of state, it remains an effective description of strange quark matter under the extreme conditions prevailing in neutron star/strange star interiors. Within the present framework, the adoption of this equation of state yields stellar radii that are in close agreement with those inferred from recent observations of compact stars as well as GW events. This consistency between theoretical predictions and observational results indicates that, despite its simplicity, the model captures essential features of dense matter and supports the reliability of the results reported in this work. Furthermore, we show that the maximum mass limit of strange stars can exceed the general relativistic counterpart. Specifically, we find that a maximum mass up to 3.11 solar mass is achievable which suggests that the lighter companion of GW190814 could plausibly be a strange star.

We study the structure and representation theory of the principal W-algebra $\mathsf{W}^{\mathsf{k}}_{\mathrm{pr}}$ of $\mathsf{V}^{\mathsf{k}}(\mathfrak{psl}_{2|2})$. The defining operator product expansions are computed, as is the Zhu algebra, and these results are used to classify irreducible highest-weight modules. In particular, for $\mathsf{k} = \pm \frac{1}{2}$, $\mathsf{W}^{\mathsf{k}}_{\mathrm{pr}}$ is not simple and the corresponding simple quotient is the symplectic fermion vertex algebra. We use this fact, along with inverse hamiltonian reduction, to study relaxed highest-weight and logarithmic modules for the small $N=4$ superconformal algebra at central charges $-9$ and $-3$.

An entropy function is proposed in [Phys. Rev. Lett. 131, 251602] as a way to detect criticality even when the system size is small. In this note we apply this strategy in the search for criticality of lattice transfer matrices constructed based on the topological holographic principle. We find that the combination of strategy is indeed a cost-effective and efficient way of identifying critical boundary conditions, estimating central charges and moreover, plotting entire phase diagrams in a multi-dimensional phase space.

We present an index-based tensorial formulation for computing eigenvalues of charge operators acting on arbitrary tensor representations of unitary gauge groups. The construction follows directly from the action of Cartan generators on tensor products and the additivity of weights, leading to a compact operator acting on general \((i_p,i_q)\) tensors. This framework provides a practical bookkeeping tool for assigning charges to arbitrary-dimensional multiplets appearing in model building. Explicit applications to \(SU(2)\), \(SU(3)\), and \(SU(5)\) representations are discussed.

We define the slant sum of quiver gauge theories, a gluing on the underlying quivers that identifies a gauge vertex with a framing vertex. Under some mild assumptions, we relate torus fixed points on the corresponding Higgs branches, which are Nakajima quiver varieties. Then we prove a ``branching rule" relating the quasimap vertex functions before and after a slant sum and deduce a number of ``factorization" corollaries. Our construction is motivated by a factorization conjecture for the vertex functions of zero-dimensional quiver varieties, which can be approached inductively using the branching rule. In special cases, it also shows that vertex functions can be written as sums over reverse plane partitions, even outside ADE type. We make some conjectures for Coulomb branches reflecting what can be seen on the Higgs side and prove them in ADE type. In particular, we obtain refined character formulas for the so-called ``extremal'' irreducible modules over shifted Yangians. We also study slant sums of Coulomb branches and their quantizations. We observe that for one-dimensional framing, the slant sum of Coulomb branches is the same as the product.

We present an exact solution of entanglement entropy for the real-time dynamics following a quench from a thermal pure quantum (TPQ) state in an free fermion system. Contrast to the usual linear growth and saturate behavior, the entanglement entropy exhibits a characteristic double-plateau structure. We obtain this behavior exactly using three complementary approaches: two-dimensional (2D) conformal field theory (CFT) on the Klein bottle, an exact numerical evolution based on the matrix Riccati equation, and an asymptotically exact quasiparticle picture.

We analytically study the gauge dependence of scalar-induced gravitational waves (SIGWs) sourced by primordial isocurvature perturbations during radiation domination (RD), working across nine gauges. Through analytical integrations of the kernels supported by graphical comparison we identify a clear dichotomy. We find that in some gauges viz. the uniform-density (UD), total-matter (TM), uniform-curvature (UC), comoving-orthogonal (CO) and transverse-traceless (TT) gauges the energy density grows polynomially in conformal time $\eta^n$, where $n$ varies from $2$ to $8$. While in rest of the gauges viz. the longitudinal (Long.), uniform-expansion (UE), Newtonian-motion (Nm), and N-body (Nb) gauges the late-time energy spectrum converges, and SIGWs behave as radiation. For subhorizon modes ($ k\eta \gg 1 $), the divergence becomes severe, showing that SIGWs are gauge-dependent observables in this regime. We resolve it through a kernel projection that isolates the luminal, freely propagating gravitational wave components (oscillating as $\sin(k\eta)$ and $\cos(k\eta)$), eliminating spurious contributions. The resulting kernel decays as $ (k\eta)^{-1} $ and yields a finite, gauge-independent late-time spectrum, confirming that only luminal modes represent physical SIGWs.

We present a single-quench protocol that generates unitary $k$-designs with minimal control. A system first evolves under a random Hamiltonian $H_1$; at a switch time $t_s \geq t_{\mathrm{Th}}$ (the Thouless time), it is quenched to an independently drawn $H_2$ from the same ensemble and then evolves under $H_2$. This single quench breaks residual spectral correlations that prevent strictly time-independent chaotic dynamics from forming higher-order designs. The resulting ensemble approaches a unitary $k$-design using only a single control operation -- far simpler than Brownian schemes with continuously randomized couplings or protocols that apply random quenches at short time intervals. Beyond offering a direct route to Haar-like randomness, the protocol yields an operational, measurement-friendly definition of $t_{\mathrm{Th}}$ and provides a quantitative diagnostic of chaoticity. It further enables symmetry-resolved and open-system extensions, circuit-level single-quench analogs, and immediate applications to randomized measurements, benchmarking, and tomography.

We show that a small charged probe near a spherical topological insulator causes the latter to rotate around a symmetry axis defined by the center of the sphere and the position of the charge outside the latter. The rotation occurs when the distance from the charge to the center of the sphere is changed. This phenomenon occurs due to induced static fields and is a consequence of the axion electrodynamics underlying the electromagnetic response of a topological insulator. Assuming a regime where the charged probe can be regarded as a point charge $q=Ne$, where $N$ is a positive integer and $e$ is the elementary electric charge, we obtain that the rotation frequency is given by $\omega=(N\alpha)^2\Upsilon(\epsilon,d/a)/I$, where $I$ is the moment of inertia, $\alpha$ is the fine-structure constant, and the function $\Upsilon$ depends on the dielectric constant $\epsilon$ and the relative distance $d/a$ of the charge from the center of the sphere of radius $a$. Since the point charge also induces Hall currents on the surface, we compute also their associated angular momentum. This allows us to derive an exact expression for the electronic velocity on the surface as a function of $a/d$.

The quantum modularity conjecture, first introduced by Don Zagier, is a general statement about a relation between $\mathfrak{sl}_2$ quantum invariants of links and 3-manifolds at roots of unity related by a modular transformation. In this note we formulate a strong version of the conjecture for Witten--Reshetikhin--Turaev invariants of closed geometric, not necessarily hyperbolic, 3-manifolds. This version in particular involves a geometrically distinguished $SL(2,\mathbb{C})$ flat connection (a generalization of the standard hyperbolic flat connection to other Thurston geometries) and has a statement about the integrality of coefficients appearing in the modular transformation formula. We prove that the conjecture holds for Brieskorn homology spheres and some other examples. We also comment on how the conjecture relates to a formal realization of the $\mathfrak{sl}_2$ quantum invariant at a general root of unity as a path integral in analytically continued $SU(2)$ Chern--Simons theory with a rational level.

We explore the experimental predictions of the local scale invariant, non-Hermitian pilot-wave (de Broglie-Bohm) formulation of quantum theory introduced in arXiv:2601.03567. We use Weyl's definition of gravitational radius of charge to obtain the fine-structure constant for non-integrable scale effects $\alpha_S$. The minuteness of $\alpha_S$ relative to $\alpha$ ($\alpha_S/\alpha \sim 10^{-21}$) effectively hides the effects in usual quantum experiments. In an Aharonov-Bohm double-slit experiment, the theory predicts that the position probability density depends on which slit the particle trajectory crosses, due to a non-integrable scale induced by the magnetic flux. This experimental prediction can be tested for an electrically neutral, heavy molecule with mass $m \sim 10^{-19} \text{g}$ at a $\sim 10^5 \text{ esu}$ flux regime. We analyse the Weyl-Einstein debate on the second-clock effect using the theory and show that spectral frequencies are history-independent. We thereby resolve Einstein's key objection against local scale invariance, and obtain two further experimental predictions. First, spectral intensities turn out to be history-dependent. Second, energy eigenvalues are modified by tiny imaginary corrections that modify spectral linewidths. We argue that the trajectory dependence of the probabilities renders our theory empirically distinguishable from other quantum formulations that do not use pilot-wave trajectories, or their mathematical equivalents, to derive experimental predictions.

We study tropicalisations of quasi-automorphisms of cluster algebras and show that their induced action on the g-vectors can be realized by tropicalising their action on the homogeneous $\hat{y}$ (or $\mathcal{X}$) variables of a chosen initial cluster. This perspective allows us to interpret the action on g-vectors as a change of coordinates in the tropical setting. Focusing on Grassmannian cluster algebras, we analyse tropicalisations of quasi-automorphisms in detail. We derive tropical analogues of the braid group action and the twist map on both g-vectors and tableaux. We introduce the notions of unstable and stable fixed points for quasi-automorphisms, which prove useful for constructing cluster monomials and non-real modules, respectively. As an application, we demonstrate that the counts of prime non-real tableaux with a fixed number of columns in $\mathrm{SSYT}(3, [9])$ and $\mathrm{SSYT}(4, [8])$, arising from the braid group action on stable fixed points, are governed by Euler's totient function. Furthermore, we apply our findings to scattering amplitudes in physics, providing a novel interpretation of the square root associated with the four-mass box integral via stable fixed points of quasi-automorphisms of the Grassmannian cluster algebra $\CC[\Gr(4,8)]$.

The junction conditions for general theories of gravity based on actions that depend on arbitrary functions of the curvature scalar invariants (including differential invariants) are obtained using the distributional formalism. In case of the existence of thin shells, a general expression for the shell energy-momentum tensor is presented. Generalized Israel equations are also obtained. The conditions for a proper matching, without shells, are derived. The main results are: (i) shells arise if the $m$th-covariant derivative of the Riemann tensor is continuous at the matching hypersurface, where $m$ is the maximum order of differentiation appearing in the Lagrangian density; (ii) a proper junction without thin shells requires further that the $(m+1)$-th derivative be also continuous, (iii) theories with $m=0$ that are quadratic in the scalar curvature invariants are special and unique for they allow for discontinuities of the Riemann tensor resulting in the existence of thin shells and {\em gravitational double layers} and (iv) General Relativity and $F(R)$ theories are extraordinary theories that admit shells of curvature (i.e. impulsive gravitational waves) because other theories require the absence of jumps of the second fundamental form across the matching hypersurface. For proper junctions, the continuity across the matching hypersurface of the normal components of the energy-momentum tensor is proven to be a {\em universal} property, independently of the field equations, thereby providing important necessary conditions for any matching in any gravitational theory. All results are derived for a minimal coupling with the matter, but the strategy would be analogous for more general couplings.

In this work, we scrutinize the thermodynamic properties of the Simpson-Visser (SV) spacetime. Working within Einstein gravity coupled to nonlinear electrodynamics (NLED) and a scalar field with negative kinetic energy, we rederive the solution in a formulation where the integration constants do not explicitly appear in the action, allowing them to vary consistently in the thermodynamic analysis. Using the Euclidean method, we show that the regular spacetime structure modifies the boundary contributions to the conserved charge associated with time translations, allowing the NLED sector to cancel the mass term and yielding a black hole with vanishing thermodynamic mass. Nevertheless, the spacetime admits a conserved magnetic charge and describes a regular black hole with a single horizon, finite temperature, and entropy, while the first law of thermodynamics holds in a modified form. We further compare this solution with the corresponding scalar-free singular black hole obtained when the regular parameter vanishes. Placing the two configurations in the same heat bath with identical temperature and magnetic chemical potential, we find that the SV regular black hole always has a larger free energy, indicating that the scalar-free singular configuration is thermodynamically preferred.