184,749 papers in this slice of arXiv.
Prateek Agrawal, Gaurang Ramakant Kane, Vazha Loladze
In holography, four-dimensional confining gauge theories are often modelled by five-dimensional Einstein--scalar gravity by choosing a specific form of the scalar potential. In a large class of non-conformal theories, we show that a predictive structure emerges for the thermal confinement transition by generalising the gravitational dual to D+1 dimensions and using a 1/D
Lorenzo Gavassino
Quasi-hydrodynamics describes systems with quasi-conserved degrees of freedom, namely observables that relax on timescales that are finite but parametrically longer than microscopic relaxation times. Examples include kinetic chemistry and linear viscoelasticity. Here, we develop a rigorous effective-field-theory framework for linear quasi-hydrodynamics from kinetic-type theories. Starting from any linearized, causal kinetic-like theory endowed with slow degrees of freedom, we show that the exact dynamics of conserved and quasi-conserved observables admits a systematic expansion in the fast relaxation timescale. At zeroth order, the resulting equations form a causal, symmetric-hyperbolic theory belonging to the appropriate transient-hydrodynamic universality class, establishing Israel-Stewart-like dynamics as the universal description of slow relaxation modes. Higher-order corrections can be computed systematically and inherit universal symmetry, Onsager, positivity, and causality constraints from the underlying microscopic theory.
Ekapob Kulchoakrungsun, Daris Samart
We study transverse vector perturbations in ghost-free extended quasidilaton massive gravity without a quasidilaton kinetic term, in the presence of minimal matter. In vacuum, we recover the known result that the kinetic coefficient KV of the gravitational vector modes vanishes on the self-accelerating branch J=0, so those modes are infinitely strongly coupled at linear order. We then add a canonical scalar field and a single Abelian vector (Maxwell or Proca). After integrating out the auxiliary shift, we find the same KV as in vacuum. The scalar matter has no transverse perturbation; it enters the unsimplified shift constraint, but those terms cancel once the Friedmann equation is used. A Maxwell or Proca field with vanishing isotropic background does not mix with the gravitational vectors at quadratic order. Minimal matter therefore leaves KV=0 on Branch II. We do not claim that the modes are absent from the nonlinear theory. We do conclude that ordinary minimal matter is not enough to make the vector sector perturbatively healthy on this branch. If we need healthy gravitational vector modes at the linear level, Branch I is the branch to use.
Inyong Cho
We investigate the quadratic-order effective energy--momentum tensor (2EMT) of scalar cosmological perturbations on uniform-density hypersurfaces during slow-roll inflation. The 2EMT is constructed from terms quadratic in the linear metric and inflaton perturbations, and is therefore a gauge-fixed effective source rather than a gauge-invariant observable. We impose the complete scalar gauge conditions δρ=0 and E=0, express all perturbations in terms of the Bardeen potential Ψ, and evaluate the Fourier-space 2EMT in the long- and short-wavelength domains. We distinguish the ``strict'' infrared and ultraviolet limits from the ``intermediate'' regimes. The uniform-density and comoving results agree in the strict infrared limit. In the intermediate infrared regime, the dominant leading order remains the same, while explicit finite-gradient corrections distinguish the two gauges. In the ultraviolet, the 2EMT is enhanced by 1/ε due to the slowly varying matter clock, ρ0′∝ε, and the leading uniform-density 2EMT terms exhibit an additional enhancement by 1/σ22 (σ2≡H/k) from the Laplacian term. The intermediate ultraviolet expansion makes the subleading gradient hierarchy explicit without changing the leading terms. We compare these results with newly recalculated longitudinal, spatially-flat, and comoving expressions, displayed in a more explicit form than in the earlier analysis. The comparison shows that the gauge dependence is structured: uniform-density and comoving slicings coincide for adiabatic super-Hubble modes, whereas the longitudinal and spatially-flat gauges are slow-roll suppressed in the strict infrared and become gradient dominated in the intermediate infrared.
Naoto Maki, Kazunori Kohri
Motivated by recent DESI results suggesting dynamical dark energy, we investigate the thawing scenario in quintessence with an exponential potential, V=V0e−λφ/mpl, by analytically expanding the deviation of the equation of state parameter wφ from −1 in powers of λ. In addition to the previously known leading-order result at O(λ2), we derive the O(λ4) correction as a function of the density parameter Ωφ. We show that a consistent determination of the redshift dependence of wφ through O(λ4) requires corrections to the background expansion. We obtain the required correction by expanding Ωφ in powers of λ around its ΛCDM value. Comparison with numerical solutions demonstrates that the O(λ4) expansion provides a more accurate approximation than the leading-order result. Our analytical approximation, which consistently incorporates the O(λ4) correction, will provide a potentially useful tool for distinguishing the exponential quintessence model from other dark energy models in future observations.
Momo Hayashi, Kazumitsu Sakai
Dyson universality typically manifests itself in local eigenvalue statistics. Here we show that its signature survives a nonlinear inverse-spectral reconstruction and reappears in the matrix geometry of the reconstructed operator. Using a dressing transformation, we map each unfolded spectrum to a deformation f(x) of a fixed harmonic oscillator and represent it in the common oscillator basis by F_mn= m|f|n. We resolve the matrix-element weight into shells of fixed distance d=∣m−n∣, corresponding to the energy-transfer channels of the reference oscillator, and characterize the resulting distribution by distance-shell moments. Independently calibrated on Gaussian β-ensembles, these moments vary smoothly with β and distinguish the GOE, GUE, and GSE. With this calibration fixed, applying the same diagnostic to the nontrivial zeros of the Riemann zeta function places the reconstructed operators in the GUE sector. Thus, the GUE character of the zeros is recovered not through direct statistics of the input levels, but from the distance-resolved geometry of the reconstructed operator.
Amit Vikram
We identify a general mechanism for the finite-time thermalization of macroscopic observables, such as coarse-grained charge densities, in terms of elementary forms of the quantum dynamics of initial states: (1) aperiodicity, which provides a computable measure of (2) a dynamical partially ergodic exploration of the Hilbert space. Specifically, this mechanism predicts the equilibration of all (concentrated) macroscopic observables, in almost all states in an initial ensemble and almost all times within finite and longer intervals, given only the observable-independent information that the return probability of the ensemble of initial states is small over a finite time range. As a special case, it also accesses standard results on equilibration over infinitely long times in terms of (stronger versions of) the effective dimension of initial state delocalization in the energy eigenbasis. Our results incorporate macroscopic thermalization into the domain of operational quantum statistical mechanics, recently developed to provide finitely computable criteria for microscopic thermalization. We discuss an overall characterization of this approach as establishing connections between (1) the decay of a (theoretically or experimentally) computable probe indicating memorylessness, (2) a fundamental invariant mechanism in terms of the alignment of observables or states in the Hilbert space, and (3) predicting different natural forms of (classical and) quantum thermalization, most of which rigorously recover conventional eigenstate-based descriptions of infinite-time thermalization as a special case but provide stronger accessible predictions over finite observation times in the thermodynamic limit.
Hao Xu
We propose a unified physical principle for entanglement harvesting: the entanglement that two localized detectors can extract from a quantum field is determined solely by how localized the field's effective spectral density is. We demonstrate this in an analytically solvable model of two qubits coupled to a leaky single-mode cavity, which in turn couples to a continuous electromagnetic bath, and derive the maximum harvestable concurrence in closed form, Cmax(Q)=2e−π/(2Q)(1+e−π/(2Q))/(1+3e−π/Q), where Q≡∣Δ∣/κ is the ratio of the qubit-cavity detuning Δ to the cavity linewidth κ. In the high-Q limit, Cmax≃1−π2/(16Q2), so the entanglement is robust against cavity loss; in the low-Q limit it decays exponentially to zero, consistent with the irreversible-reservoir character of a continuous field, where maximal entanglement is unattainable. Since Q is proportional to the inverse participation ratio (IPR) of the effective spectral density, it is the single dimensionless parameter governing the crossover from deterministic gate-based entanglement (Q→∞) to vacuum harvesting (Q→0). Our framework operationalizes the Reeh-Schlieder theorem by quantifying the fraction of vacuum correlations accessible to localized detectors. It also reveals a formal correspondence of the maximal concurrence with the IPR, analogous to the conductivity-participation-ratio relation in Anderson localization. The predicted Cmax(Q) curve is, in principle, directly observable in superconducting circuit QED experiments.
Siddhartha Sankar Borah, Dhruba Jyoti Gogoi, Kalyan Bhuyan
We investigate the thermodynamic behaviour of an AdS black hole arising from nonlinear electrodynamics-corrected gravity, incorporating quantum effects through thermal fluctuations. From the Einstein--Euler--Heisenberg framework, we consider the modified black hole solution and analyse its thermodynamic properties in the extended phase space. Logarithmic and inverse-area corrections to the entropy are obtained, leading to modified expressions for enthalpy, internal energy, Helmholtz free energy and Gibbs free energy. The corrected specific heat exhibits multiple divergences and sign changes, signalling genuine second-order phase transitions and revealing a quantum-stabilized microscopic phase followed by universal macroscopic instability. Our results demonstrate that thermal fluctuations qualitatively restructure the thermodynamic phase space and highlight the dominant role of quantum corrections in governing the black hole stability.
Tianhao Wu
String-derived higher-curvature scalar--tensor gravities encode microscopic coupling data in boundary response, raising the question of whether holographic observables can reconstruct the underlying higher-dimensional parameters. We answer this question for the five-dimensional string-derived Lovelock--Horndeski (SDLH) theory on its exact linear-dilaton asymptotically locally AdS branch, constructing the renormalized generating functional for an arbitrary boundary metric and spacetime-dependent scalar source. A boundary-covariant radial hierarchy unifies the variational problem, local backreaction, logarithmic obstruction, finite one-point functions, and Ward identities. Two response determinants organize the recursion, resonant obstructions, and metric--scalar mixing. The Weyl anomaly condenses into an Euler density, a Weyl-squared density, and a single curvature--scalar square whose paired variations generate the metric and scalar obstructions. The resulting renormalized functional carries string-selected coupling data into boundary geometry, operator response, anomaly coefficients, and a calculable interface with gravitational observables. On the regular branch, four scalar-normalization-invariant holographic combinations admit a global rational inverse to the continuous reduced couplings. At fixed compactification dimension the map has maximal rank, while the curvature-anomaly sum reconstructs the higher-dimensional Gauss--Bonnet coefficient without sign ambiguity. Holographic response thus provides an explicit, overdetermined boundary fingerprint of the underlying string reduction.
Nelson R. F. Braga, Alexsandre L. Ferreira
Recently, it was demonstrated that the disagreement between lattice calculations and holographic models, regarding rotational effects in the quark-gluon plasma (QGP), occurs due to different choices of reference frames. While a static observer measures a confinement temperature that decreases with rotation, one in a co-rotating frame finds the opposite behavior. Both results are correct, and a comprehension of the frame-dependency of the critical temperature is a significant step in the description of the QGP under rotation. In this article, we generalize this previous holographic result by describing the plasma through the most general Myers-Perry black hole solution. This breaks the spherical symmetry present in the equal angular momentum case, considered before. As a consequence, the local temperature measured by a co-rotating observer has a non-trivial angular dependence: it can decrease, increase or even behave non-monotonically when rotational velocity increases.
Sungjoon Kim
Gang-Kim-Stubbs theory Tn --- a pioneering 3d bulk description of M(2n+3,2) Virasoro minimal model as N=4 rank-0 superconformal field theory upon topological A-twist --- is derived from the compactification of a pair of parallel M5-branes on lens space L(2n+3,2) with a single vertex removed. From this perspective, we propose a family of 3d N=2 abelian gauge theories arising from the punctured L(2n+3,1) lens space whose infrared phases realize the unitary member in the Galois orbit of M(2n+3,2) modular tensor category. We also conjecture self-mirror rank-0 fixed points from amphichirality condition of the lens space.
Yongjiang Xu, Weixin Sun, Chushun Tian +1
In theoretical physics, finding connections between problems that appear in distinct contexts is an important way to leapfrog progresses, often by illuminating deep aspects that may otherwise seem obscure. In this paper, we consider in 2d CFTs the phenomenon of forbidden singularities in auto-correlation functions -- a key signature of eigenstate thermalization. We show that they correspond to phase transitions in the context of eigenstates. The connection is made explicit by utilizing the AGT correspondence, which relates eigenstate auto-correlations to the Nekrasov partition functions describing an instanton gas of the N=2 SUSY gauge theories. We show that by taking the counter-part of the heavy-light limit, two phases emerge for the instanton gas. They are dominated by configurations represented by string-like Young tableaux with distinct structures and thermodynamic properties, which bare resemblance to the confined and the deconfined phases. A phase transition occurs as instantons proliferate from one side, in a manner that mimics the Lee-Yang theory. We work out the critical fugacity and find it corresponding exactly to the forbidden singularity.
Yongjiang Xu, Weixin Sun, Chushun Tian +1
As phase transitions in isolated quantum systems remain elusive, here we show how a thermodynamic-like phase transition, falling into the Lee-Yang paradigm, can arise in systems displaying eigenstate thermalization. Specifically, we show that in holographic conformal field theories, the eigenstate expectation of the auto-correlation function can be mapped to the partition function Zgauge(z) of a virtual interacting instanton gas, with the conformal mapping of the imaginary time: z=1−e−τ and the central charge c mimicking the instanton fugacity and volume, respectively. We find that akin to the Lee-Yang paradigm, for c→∞ a pair of complex conjugate zeros of Zgauge(z) move to the real axis located at the famous forbidden singularity. Passing through the singularity the system transits from the low- to high-fugacity phase, accompanied by dramatic changes in scaling behaviors of the free energy and dominant microscopic configurations. Our findings indicate that physics of phase transitions from eigenstate thermalization is very rich.
W. A. Sabra, R. Slim
We construct four families of spacetime metrics depending on a single variable for a broad class of D-dimensional gravitational theories coupled to scalar and Abelian gauge fields. As applications of the general formalism, we derive one-variable solutions of ungauged N=2, D=4 supergravity coupled to vector multiplets. We also obtain explicit solutions for a consistent truncation of N=8, D=4 supergravity, as well as for theories whose scalar fields parametrize the symmetric coset manifolds SL(N,R)/SO(N,R). In all cases, the geometry of the scalar manifold plays a central role in determining the structure of the resulting solutions with nontrivial scalar and gauge field configurations.
Vadim Asnin
A novel approach to a computation of vacuum amplitude for a single scalar field in any number of dimensions with arbitrary potential on a lattice is proposed. The computation involves symmetrization of kinetic exponential factor in the path integral over all permutations of lattice sites and Waring decomposition of the symmetrized expression.
Matvei Fedin, Kirill Gubarev, Andrey Morozov
The main goal of tomography is the reconstruction of density function out of its line integrals (integral measurements of this density along x-ray lines). Such construction is possible and known as inverse x-ray/Radon transformations. We are interested in generalization of this problem to the case of particles. For this we need to limit the speed of these particles, otherwise the problem is reduced to the previous one. The question we discuss in this paper is how low can this speed be depending on the parameters of the studied potential. We study this problem using simple theoretical examples and Machine Learning pipeline to restore the potential.
Massimo D'Elia, Fabio Siliberto, Kevin Zambello
We investigate the topological properties of QCD across the finite temperature Roberge-Weiss transition, which is found for particular values of the imaginary baryon chemical potential. Our study is conducted for Nf=2+1+1 QCD with physical quark masses, discretized via stout improved staggered fermions and considering mostly two different values of the compactifed dimension, Nt=8
Patharadanai Nuchino, Parinya Karndumri
We study a number of supersymmetric AdS4×Σ solutions with Σ being a topological disk with non-trivial U(1) holonomy on the boundary or a ``half-spindle'' from matter-coupled F(4) gauged supergravity. The gauged supergravity is coupled to three vector multiplets with SO(3)×SO(3) gauge group. The resulting solutions preserve eight supercharges and SO(2)×SO(2) or SO(2)diag symmetries and are expected to be dual to N=2 SCFTs in three dimensions arising from compactifications of five-dimensional N=2 SCFT on a half-spindle. All of the solutions lie within the U(1)×U(1) subsector of the matter-coupled F(4) gauged supergravity that can be embedded in massive type IIA theory. After uplifted to ten dimensions, the solutions can be interpreted as a system of D4-D8-branes wrapped on Σ. Some of the solutions are asymptotic to a locally AdS6 geometry and can be identified as codimension-2 conformal defects within the N=2 SCFT in five dimensions. For these solutions, the circle inside Σ decompactifies in the AdS6 limit rendering the holographic free energy infinite. There also exist solutions with finite free energy in the dual three-dimensional SCFTs. In addition, we show that the results both extend the previously known solutions and provide a novel class of solutions.
Renata Kallosh, Andrei Linde, Yusuke Yamada
Hybrid α-attractor models Kallosh:2022ggf can have significantly greater values of ns and smaller r, while preserving the relation r≅3α(1−ns)2, which is valid for exponential T- and E-models at large values of the inflaton field. Here we study single-field α-attractors with features inspired by hybrid models: one can uplift the potential, and one can also have a waterfall regime that leads to a premature termination of inflation near the critical point φc. This allows one to increase the effective number of e-foldings Nc in formulas like ns≃1−Nc2, r≃Nc212α. By changing the waterfall's steepness and location, one can continuously move the predictions along the curves with r≅3α(1−ns)2 as ns increases and r decreases. We also study the effect of waterfall insertions and uplift on ns in quintessential α-attractors that describe inflation and dynamical dark energy.