The continued development of models that propose the existence of fractional topological objects in the Yang-Mills vacuum has called for a quantitative method to study the topological structure of $\mathrm{SU}(N)$ gauge theory. We present an original numerical algorithm that can identify distinct topological objects in the nontrivial ground-state fields and approximate the net charge contained within them. This analysis is performed for SU(3) color at a range of temperatures crossing the deconfinement phase transition, allowing for an assessment of how the topological structure evolves with temperature. We find a promising consistency with the instanton-dyon model for the structure of the QCD vacuum at finite temperature. Several other quantities, such as object density and radial size, are also analyzed to elicit a further understanding of the fundamental structure of ground-state gluon fields.

Roy-equation analysis on lattice data of $\pi \pi$ scattering phase shifts at $m_{\pi }=391\mathrm{MeV}$ reveals that the lowest $f_0$ meson becomes a bound state under this condition. In addition, there is a pair of complex poles below threshold generated by crossing symmetry [X.-H. Cao et al., Phys. Rev. D 108, 034009 (2023)]. We use the $N/D$ method to partially recover crossing symmetry of the $O(N)$ $\sigma$ model amplitude at leading order of $1/N$ expansion, and qualitatively reproduce the pole structure and pole trajectories with varying pion masses as revealed by Roy-equation analyses. The $\sigma$ pole trajectory with varying temperature is also discussed and found to be similar to its properties when varying $m_{\pi }$. As the temperature increases, the complex $\sigma$ poles firstly move from the second Riemann sheet to the real axis becoming two virtual state poles, and then one virtual state pole moves to the first sheet turning into a bound state pole and finally tends to the pion pole position at high temperature which is as expected from the chiral symmetry restoration. Our results provide further evidence that the lowest $f_0$ state extracted from experiments and lattice data plays the role of the $\sigma$ meson in the spontaneous breaking of chiral symmetry. Finally, we also briefly discuss the problems of the effective potential in the situation when $m_{\pi }$ and the temperature become large.

In this work we investigate the exclusive production of a pair of light neutral mesons in $e^{+}{e}^{-}$ annihilation, where the final state bears an even $C$-parity. The production processes can be initiated via the photon fragmentation or the nonfragmentation mechanism. While the fragmentation contribution can be rigorously accounted, the nonfragmentation contributions are calculated within the framework of collinear factorization, where only the leading-twist light-cone distribution amplitudes (LCDAs) of mesons are considered. Mediately solely by the nonfragmentation mechanism, the production rates of double light neutral pseudoscalar mesons are too small to be observed at the commissioning $e^{+}{e}^{-}$ facilities. In contrast, the production rates of a pair of light neutral vector mesons are greatly amplified owing to the significant kinematic enhancement brought by the fragmentation mechanism. It is found that, at $\sqrt{s}=3.77\mathrm{GeV}$, after including the destructive interference between the nonfragmentation and fragmentation contributions, the production rates for $e^{+}{e}^{-}\to {\rho }^0{\rho }^0$ and ${\rho }^0\omega$ can be lowered by about 10% and 30% relative to the fragmentation predictions. Future precise measurement of these exclusive double neutral vector meson production channels at BESIII experiment may provide useful constraints on the LCDAs of light vector mesons.

Accelerator based neutrino oscillation experiments seek to measure the relative number of electron and muon (anti)neutrinos at different $L/E$ values. However high statistics studies of neutrino interactions are almost exclusively measured using muon (anti)neutrinos since the dominant flavor of neutrinos produced by accelerator based beams are of the muon type. This work reports new measurements of electron (anti)neutrinos interactions in hydrocarbon, obtained by strongly suppressing backgrounds initiated by muon flavor (anti)neutrinos. Double differential cross sections as a function of visible energy transfer, $E_{\text{avail}}$, and transverse momentum transfer, $p_T$, or three momentum transfer, $q_3$ are presented.

We prove two new infinite families of holographic entropy inequalities. A key tool is a graphical arrangement of terms of inequalities that is based on entanglement wedge nesting. It associates the inequalities with tessellations of the torus and the projective plane, which reflect a certain topological aspect of entanglement wedge nesting. The inequalities prove a prior conjecture about the holographic entropy cone. We discuss their relation to black hole physics and differential entropy, and sketch applications to quantum error correction, quantifying randomness of quantum states, and others.

While a wide variety of astrophysical and cosmological phenomena suggest the presence of dark matter, all evidence remains via its gravitational effect on the known matter. As such, it is conceivable that this evidence could be explained by a modification to gravitation and/or concepts of inertia. Various formulations of modified gravity exist, each giving rise to several noncanonical outcomes. This motivates us to propose an experiment searching for departures from (quantum) Newtonian predictions in a bipartite setting with gravitational accelerations $\lesssim {10}^{-10}\mathrm{m}/{\mathrm{s}}^2$, i.e., where the effective force needs to be stronger than Newtonian to account for the dark matter effects. Since quantum particles naturally source weak gravitation, their nonrelativistic dynamics offers opportunities to test this small acceleration regime. We show that two nearby mesoscopic quantum masses accumulate significantly larger entanglement in modified gravity models, such as the modified Newtonian dynamics. Our calculations include Casimir-Polder forces as well as tidal effects next to the surface of the Earth, and confirm that entanglement is observable within the limits imposed by environmental decoherence. We demonstrate how the temperature can be fine-tuned such that modified gravity is certified simply by witnessing the entanglement generated from uncorrelated thermal states, eliminating the need for precise noise characterization. Overall, the required parameters could be realized in a tabletop experiment.

Recently, several regional pulsar timing array collaborations, including CPTA, EPTA, PPTA, and NANOGrav, have individually reported compelling evidence for a stochastic signal at nanohertz frequencies. This signal originates potentially from scalar-induced gravitational waves associated with significant primordial curvature perturbations on small scales. In this Letter, we employ data from the EPTA DR2, PPTA DR3, and NANOGrav 15-year dataset to explore the speed of scalar-induced gravitational waves using a comprehensive Bayesian analysis. Our results suggest that, to be consistent with pulsar timing array observations, the speed of scalar-induced gravitational waves should be $c_g\gtrsim 0.61$ at a 95% credible interval for a log-normal power spectrum of curvature perturbations. Additionally, this constraint aligns with the prediction of general relativity that $c_g=1$ within a 90% credible interval. Our findings underscore the capacity of pulsar timing arrays as a powerful tool for probing the speed of scalar-induced gravitational waves.

Very recently, the major pulsar timing array collaborations, including CPTA, EPTA, InPTA, NANOGrav, and PPTA, reported their results from searches for an isotropic stochastic gravitational wave background (SGWB), collectively representing positive evidence for a SGWB. In this work, we assessed the credibility of interpreting the Hellings-Downs correlated free-spectrum process of EPTA, PPTA, and NANOGrav as either the result of supermassive black hole binary mergers or various stochastic SGWB sources that originated in the early Universe, including first-order phase transitions, cosmic strings, domain walls, and large-amplitude curvature perturbations. Our results show that the current new datasets do not distinctly favor one specific SGWB source over the others based on Bayesian analysis. We also place constraints on new physics for the SGWB sources.

The global symmetries of a $D$-dimensional quantum field theory (QFT) can, in many cases, be captured in terms of a ($D+1$)-dimensional symmetry topological field theory (SymTFT). In this work we construct a ($D+1$)-dimensional theory which governs the symmetries of QFTs with multiple sectors which have connected correlators that admit a decoupling limit. The associated symmetry field theory decomposes into a SymTree, namely a treelike structure of SymTFTs fused along possibly nontopological junctions. In string-realized multisector QFTs, these junctions are smoothed out in the extradimensional geometry, as we demonstrate in examples. We further use this perspective to study the fate of higher-form symmetries in the context of holographic large $M$ averaging where the topological sectors of different large $M$ replicas become dressed by additional extended operators associated with the SymTree.

In this paper, we construct a general bulk wave packet in the $\mathrm{AdS}/\mathrm{CFT}$ correspondence. This wave packet can be described both in bulk and conformal field theory (CFT) descriptions. Then, we compute the time evolution of the energy density of this wave-packet state on the vacuum in the CFT picture of ${\mathrm{AdS}}_3/{\mathrm{CFT}}_2$. We find that the energy density of the wave packet is localized at two points, which means that the bulk wave packet corresponds to two light-like particle-like objects in the CFT picture. Our result implies that the entanglement wedge reconstruction given by Almheiri et al. [Bulk locality and quantum error correction in $\mathrm{AdS}/\mathrm{CFT}$, J. High Energy Phys. 04 (2015) 163] is invalid.

The linear dilaton (LD) background is the keystone of a string-derived holographic correspondence beyond ${\mathrm{AdS}}_{d+1}/{\mathrm{CFT}}_d$. This motivates an exploration of the ($d+1$)-dimensional linear dilaton spacetime (${\mathrm{LD}}_{d+1}$) and its holographic properties from the low-energy viewpoint. We first notice that the ${\mathrm{LD}}_{d+1}$ space has simple conformal symmetries, that we use to shape an effective field theory (EFT) on the LD background. We then place a brane in the background to study holography at the level of quantum fields and gravity. We find that the holographic correlators from the EFT feature a pattern of singularities at certain kinematic thresholds. We argue that such singularities can be used to bootstrap the putative $d$-dimensional dual theory using techniques analogous to those of the cosmological bootstrap program. Turning on finite temperature, we study the holographic fluid emerging on the brane in the presence of a bulk black hole. We find that the holographic fluid is pressureless for any $d$ due to a cancellation between Weyl curvature and dilaton stress tensor, and verify consistency with the time evolution of the theory. From the fluid thermodynamics, we find a universal temperature and Hagedorn behavior for any $d$. This matches the properties of a ${\mathrm{CFT}}_2$ with large $T\overline{T}$ deformation, and of little string theory for $d=6$. We also find that the holographic fluid entropy exactly matches the bulk black hole Bekenstein-Hawking entropy. Both the fluid equation of state and the spectrum of quantum fluctuations suggest that the $d$-dimensional dual theory arising from ${\mathrm{LD}}_{d+1}$ is generically gapped.

We study a model comprising $N$ flavors of Kähler Dirac fermion propagating on a triangulated two-dimensional disk which is constrained to have a negative average bulk curvature. Dirichlet boundary conditions are chosen for the fermions. Quantum fluctuations of the geometry are included by summing over all possible triangulations consistent with these constraints. We show in the limit $N\to \infty$ that the partition function is dominated by a regular triangulation of two-dimensional hyperbolic space. We use strong coupling expansions and Monte Carlo simulation to show that in this limit boundary correlators of the fermions have a power law dependence on boundary separation as one expects from holography. However, we argue that this behavior breaks down for any finite number of massive fields in the thermodynamic limit and quantum fluctuations of the bulk geometry drive the theory into a nonholographic phase. In contrast, for massless fermions, we find evidence that the boundary is conformal even for finite $N$. This is consistent with theoretical results in quantum Liouville theory.

We study two-dimensional $\mathcal{N}=(0,2)$ and $\mathcal{N}=(0,4)$ theories derived from compactifying class $\mathcal{S}$ theories on $S^2$ with a topological twist. We present concise expressions for the elliptic genera of both classes of theories, revealing the topological quantum field theory structure on Riemann surfaces $C_{g,n}$. Furthermore, our study highlights the relationship between the left-moving sector of the (0,2) theory and the chiral algebra of the four-dimensional $\mathcal{N}=2$ theory. Notably, we propose that the (0,2) elliptic genus of a theory of this class can be expressed as a linear combination of characters of the corresponding chiral algebra.

It is well known that (possibly nonunique) suitable field dynamics can be prescribed in spacetimes with timelike boundaries by means of appropriate boundary conditions. In [R. M. Wald, J. Math. Phys. 21, 2802 (1980)], Wald derived a conserved energy functional for each prescribed dynamics. This conserved energy is related to the positive self-adjoint extensions of the spatial part $A$ of the wave equation ${\partial }^2\mathrm{\Phi }/\partial t^2=-A\mathrm{\Phi }$ ($A$ may not be, in principle, essentially self-adjoint). This is quite surprising since the canonical energy is not conserved in these cases. In this paper, we rederive this energy functional from an action principle (with appropriate boundary terms) following [A. A. Saharian, Phys. Rev. D 69, 085005 (2004)] and consider field dynamics arising from nonpositive self-adjoint extensions of $A$. The spectrum of the resulting theory fails to be positive and unstable mode solutions for classical fields come to light. By studying fields in half-Minkowski spacetime, we illustrate that these unstable classical solutions come as a consequence of an inverted parabolic potential governing their dynamics. From the quantum mechanical point of view, this leads to an effective inverted harmonic oscillator at the boundary. We then explore these unstable modes behavior, as well as their instabilities, at the quantum level.

We obtain a Palatini-type formulation for the Galilei and Carroll expansions of general relativity, where the connection is promoted to a variable. Known versions of these large and small speed of light expansions are derived from the Einstein-Hilbert action and involve dynamical Newton-Cartan or Carroll geometry, along with additional gauge fields at subleading orders. The corresponding Palatini actions that we obtain in this paper are derived from an appropriate expansion of the Einstein-Palatini action, and the connection variable reduces to the Galilei- or Carroll-adapted connection on shell. In particular, we present the Palatini form for the next-to-leading-order Galilean action and recover the known equations of motion. We also compute the leading-order Palatini-type action for the Carrollian case and show that, while it depends on the connection variable, it reduces on shell to the known action of electric Carroll gravity, which only depends on extrinsic curvature.

In the present work, considering critical gravity as a gravity model, an electrically charged topological anti–de Sitter black hole with a matter source characterized by a nonlinear electrodynamics framework is obtained. This configuration is defined by an integration constant, three key structural constants, and a constant that represents the topology of the event horizon. Additionally, based on the Wald formalism, we explore the possibility that this configuration enjoys nontrivial thermodynamic quantities, establishing the corresponding first law of black hole thermodynamics, as well as local stability under thermal and electrical fluctuations. Additionally, via the Gibbs free energy, we note that the topology of the base manifold allows us to compare this charged configuration with respect to the thermal AdS spacetime, allowing us to obtain a Phase Transition. The quasinormal modes and the greybody factor are also calculated by considering the spherical situation. We find that the quasinormal modes exhibit a straightforward change for variations of one of the structural constants.