While von Neumann entropies for subregions in quantum field theory universally contain ultraviolet divergences, differences between von Neumann entropies are finite and well defined in many physically relevant scenarios. We demonstrate that such a notion of entropy differences can be rigorously defined in quantum field theory in a general curved spacetime by introducing a novel, covariant regulator for the entropy based on the modular crossed product. This regulator associates a type II von Neumann algebra to each spacetime subregion, resulting in well-defined renormalized entropies. This prescription reproduces formulas for entropy differences that coincide with heuristic formulas widely used in the literature, and we prove that it satisfies desirable properties such as unitary invariance and concavity. As an application, we provide proofs of the Bekenstein bound and the quantum null energy condition, formulated directly in terms of vacuum-subtracted von Neumann entropies.

Next-generation gravitational-wave observatories are expected to detect over a thousand compact binary coalescence signals daily, with some lasting from minutes to hours. Consequently, multiple signals will overlap in the time-frequency plane, generating a foreground noise that predominantly affects the low-frequency range, where binary neutron star inspiral evolution is gradual. This study investigates the impact of such foreground noise on parameter estimation for short-duration binary black hole signals, particularly those with high detector-frame masses and/or located at large redshifts. Our results show a reduction in detection sensitivity by approximately 25% when the noise power spectrum deviates by up to 50% from Gaussian noise due to foreground contamination. Despite this, using standard parameter estimation techniques without subtracting overlapping signals, we find that foreground noise has minimal impact, primarily affecting precision. These findings suggest that even in the presence of substantial foreground noise, global-fit techniques, and/or signal subtraction will not be necessary for unbiased recovery of system parameters.

The future ground- and space-based gravitational wave (GW) detectors offer unprecedented opportunities to test general relativity (GR) with greater precision. In this work, we investigate the capability of future ground-based GW detectors, the Einstein Telescope (ET) and the Cosmic Explorer (CE), and space-based GW detectors, LISA, Taiji, and TianQin, for constraining parity and Lorentz violations in gravity. We inject several typical GW signals from compact binary systems into GW detectors and perform Bayesian inferences with the modified waveforms with parity and Lorentz-violating effects. These effects are modeled in the amplitude and phase corrections to the GW waveforms with their frequency-dependence described by factors ${\beta }_{\nu }$, ${\beta }_{\mu }$, ${\beta }_{\overline{\nu }}$, and ${\beta }_{\overline{\mu }}$. Our results show that the combined observations of ET and CE will impose significantly tighter bounds on the energy scale of parity and Lorentz violations ($M_{\mathrm{PV}}$ and $M_{\mathrm{LV}}$) compared to those given by LIGO-Virgo-KAGRA (LVK) detectors. For cases with positive values of ${\beta }_{\nu }$, ${\beta }_{\mu }$, ${\beta }_{\overline{\nu }}$, and ${\beta }_{\overline{\mu }}$, the constraints on $M_{\mathrm{PV}}$ and $M_{\mathrm{LV}}$ from ground-based detectors are tighter than those from the space-based detectors. For the case of ${\beta }_{\mu }=-1$ space-based GW detectors provide constraints on $M_{\mathrm{PV}}$ that are better than current LVK observations and comparable to those from ET and CE. Additionally, space-based detectors exhibit superior sensitivity in constraining $M_{\mathrm{LV}}$ for ${\beta }_{\overline{\mu }}=-2$ case, which is approximately 3 orders of magnitude tighter than those from ground-based GW detectors. This scenario also enables bounds on the graviton mass at $m_g\lesssim {10}^{-35}\mathrm{GeV}$. These findings highlight the promising role of future GW observatories in probing fundamental physics beyond GR.

We perform full integration of the stationary axisymmetric Einstein-Maxwell-dilaton-axion (EMDA) theory with and without potential using a recently proposed generalization of Carter’s approach to spacetimes beyond type D, allowing the Killing tensor. Crucial to our construction is a new parametrization of the dilaton and axion fields based on the analyticity argument. The general solution in the ungauged case is asymptotically locally flat and contains two more parameters compared to EMDA black holes previously obtained using Harrison transformations. In the gauged case, the general solution is asymptotically anti–Sitter (AdS) and includes flat and hyperbolic topological solutions, as well as generalization of the Kerr-Sen-AdS metric with three additional parameters. Our approach can be applied to more general four-dimensional ungauged and gauged supergravities.

Recently, it has been reported that black holes (BHs) sourced by nonlinear electrodynamics (NED) can trigger unbounded superradiance, i.e., the total absorption cross section—the ratio between the absorbed flux and the incident flux of the wave—can be negative and unbounded from below. Considering the propagation of massive charged test scalar fields in the vicinity of electrically charged BH solutions based on the NED framework, we derive sufficient conditions to have an unbounded superradiant regime. We also discuss some possible general conditions that the NED electrical source associated with the geometry has to satisfy to trigger an unbounded superradiance. Our results apply to a broad family of electrically charged BH solutions (regular and singular) derived in the framework of NED minimally coupled to general relativity.

We show that the superhorizon-limit curvature perturbations are conserved at one-loop level in single-field inflation models with a transient nonslow-roll period. We take the spatially flat gauge, where the backreaction plays a crucial role for the conservation of superhorizon curvature perturbations unless the counterterms are tuned. We calculate the backreaction with the in-in formalism. In addition, we explicitly show the renormalization of the UV divergences with the counterterms.

In this work we derive two computationally efficient frequentist detection statistics that can be used in searches for gravitational-wave bursts with memory in pulsar timing data. By maximizing the likelihood ratio in two different ways we construct a coherent statistic and an incoherent statistic, which are analogs of the ${\mathcal{F}}_e$ and ${\mathcal{F}}_p$ statistics commonly used for continuous-wave searches in pulsar timing data. We show that both statistics are ${\chi }^2$-distributed with varying degrees of freedom and noncentrality parameters given by the signal-to-noise (SNR) ratio of the signal present in our data. The statistics can also be used to compute the maximum likelihood estimators of amplitude parameters of a possible gravitational-wave memory signal in pulsar timing data. We find that in the low-signal regime ($\mathrm{SNR}\lesssim 5$), the estimators are inaccurate. However, in intermediate- to high-signal regimes, we show that these estimators can accurately determine the correct signal parameters. We also study the effects of red noise on these statistics, and find that the inclusion of red noise reduces the signal-to-noise ratio for injected memory signals.

The Xenon-Argon Technology (X-ArT) Collaboration presents a study on the dynamics of pure and xenon-doped liquid argon (LAr) scintillation. Using two types of silicon photomultipliers sensitive to different wavelength ranges, we provide evidence in favor of a contribution from long-lived ($>10\mathrm{\mu }\mathrm{s}$) extreme ultraviolet (EUV) lines emitted from argon atomic states, which enhances the light yield. This component is present in both pure and xenon-doped LAr, becoming more pronounced at higher xenon concentrations, where it complements the traditional collisional energy transfer process. To explain this mechanism, we develop a comprehensive model of the Xe-doped LAr scintillation process that integrates both collisional and radiative contributions. Additionally, we investigate how xenon doping affects LAr scintillation light yield and pulse shape discrimination. Finally, we hypothesize that the EUV component may explain the emission of spurious electrons, a known challenge in light dark matter searches using noble liquids. By characterizing the scintillation dynamics in Xe-doped LAr, identifying the long-lived EUV component, and exploring the potential origin of spurious electrons, this work lays the groundwork for optimizing detector performance and advancing the design and sensitivity of future noble liquid particle detectors.

In this paper we found the dipole-nucleus scattering amplitude at high energies by summing large Pomeron loops. It turns out that the energy dependence of this amplitude is the same as for dipole-dipole scattering. It means that the Balitsky-Kovchegov equation, which has been derived to describe this scattering, can be trusted only in the limited range of energies: $z\le 2\sqrt{\kappa c}{A}^{1/6}$.

Within the framework of nonrelativistic quantum chromodynamics, this study examines the electroproduction processes $e+p\to e+B_c+\overline{c}+b$, $e+p\to e+B_s+\overline{s}+b$, and $e+p\to e+D_s+\overline{c}+s$ at lepton-hadron colliders. The differential cross sections in $\cos \theta$ and $p_T^2$ at HERA are presented. Comparisons with fragmentation contributions of $B_c$ and $D_s$ production are made. The results indicate that the detection of $B_c$ is possible at the EIC, whereas not feasible at HERA. The cross sections of $B_s$ and $D_s$ production are significant at HERA, though they are notably quark mass and renormalization scale dependent.

Multistep phase transition provides a paradigm in which a broken symmetry during phase transition can be restored, enriching the phenomena of both dark matter and baryon asymmetry. We study the dynamics of the multistep phase transition in the standard model extension with additional isospin $N$-plet scalar field ${\mathrm{\Phi }}_2$ under a discrete ${\mathbb{Z}}_2$ symmetry. We find that the multistep phase transition could be triggered if there is a moderately large coupling between the Higgs boson and the ${\mathrm{\Phi }}_2$ and this coupling is required to be larger as the mass of the ${\mathrm{\Phi }}_2$ and/or isospin increases. The first-order phase transition at the first (second) step can be realized by the thermal loop (tree-level barrier) effects. Thus, it is more likely that a detectable spectrum of gravitational waves can be produced at the second step of the phase transition.

We search for an excess of electrons and positrons in the interplanetary space from the decays of heavy neutrinos produced in nuclear reactions in the Sun. Using measurements of the electron spectra in the MeV range from Ulysses and the Solar and Heliospheric Observatory, we report the strongest direct upper bound to date on the mixing between heavy neutral leptons with MeV masses and electron neutrinos, reaching $U_e^2\simeq {10}^{-6}$ at $M_N=10\mathrm{MeV}$. Our sensitivity is predominantly constrained by the uncertainties in the propagation of electrons and positrons, particularly the diffusion coefficient in the inner Solar System, as well as the uncertainties in the astrophysical background. Enhancing our understanding of either of these factors could lead to a significant improvement in sensitivity.

We search for emergent hydrodynamic modes in real-time Hamiltonian dynamics of $2+1$-dimensional SU(2) lattice gauge theory on a quasi-one-dimensional plaquette chain, by numerically computing symmetric correlation functions of energy densities on lattice sizes of about 20 with the local Hilbert space truncated at $j_{\max }=\frac{1}{2}$. Because of the Umklapp processes, we only find a mode for energy diffusion. The symmetric correlator exhibits transport peak near zero frequency with a width approximately proportional to momentum squared at small momentum, when the system is fully quantum ergodic, as indicated by the eigenenergy level statistics. This transport peak leads to a power-law $t^{-\frac{1}{2}}$ decay of the symmetric correlator at late time, also known as the long-time tail, as well as diffusionlike spreading in position space. We also introduce a quantum algorithm for computing the symmetric correlator on a quantum computer and find it gives results consistent with exact diagonalization when tested on the IBM emulator. Finally we discuss the future prospect of searching for the sound modes.

We present results of a lattice field theory simulation of the $(2+1)\mathrm{D}$ Thirring model with $N=1$ fermion flavors, using domain wall fermions. The model exhibits a U(2)-symmetry-breaking phase transition with the potential to define a UV-stable renormalization group fixed point. The novelty is the replacement of the Shamir kernel used in all previous work with the Wilson kernel, improving the action particularly with respect to the $L_s\to \infty$ limit needed to recover U(2), now under much better control. Auxiliary field ensembles generated on ${16}^3\times 24$ with varying self-interaction strength $g^2$ and bare mass $m$ are used to measure the bilinear condensate order parameter $⟨\overline{\psi }i{\gamma }_3\psi ⟩$ with domain wall separations as large as $L_s=120$. The resulting $L_s\to \infty$ extrapolation is used to fit an empirical equation of state modeling spontaneous symmetry breaking as $m\to 0$. The fit is remarkably stable and compelling, with the fitted critical exponents ${\beta }_m\simeq 2.4$, $\delta \simeq 1.3$ differing markedly from previous estimates. The associated susceptibility exhibits a mass hierarchy in line with physical expectations, again unlike previous estimates. Schwinger-Dyson equation (SDE) solutions of the Thirring model exploiting a hidden local symmetry in the action are reviewed and analytic predictions presented for the exponents. In contrast to all previous lattice studies, the universal characteristics of the critical point revealed qualitatively resemble the SDE predictions.

Using the diabatic formalism, a rigorous generalization of the Born-Oppenheimer approximation, we study the effects of introducing simple meson-meson molecular potentials to an established diquark model for tetraquark states, and calculate mixed bound states composed of both diquark-antidiquark and meson-meson molecular components. We examine the behavior of properties of the states as one varies the parameters of the dimeson potential, and find that significant regions of parameter space occur in which one may produce mass eigenstates exactly matching the specific examples of ${\chi }_{c1}(3872)$ and ${\chi }_{c0}(3915)$. We also find regions in which a pure dimeson molecular state emerges, and study the same state properties in such cases.

We study the $B^{-}\to D^{-}{D}^0{K}_S^0$ reaction, recently analyzed by the LHCb Collaboration, where a clear signal for the exotic $T_{cs0}(2870)$ state was reported. We call attention to a small peak in the $D^0{K}_S^0$ mass distribution that could correspond to a state of the same nature as the $T_{cs0}(2870)$ ($D^{*}{\overline{K}}^{*}$ nature in the molecular picture), but with $J^P=2^{+}$. In order to magnify the signal for the state, we calculate the moments of the angle-mass distribution, which are linear in the resonance signal, rather than quadratic for the angle integrated mass distribution. We find spectra for the moments with a strength far bigger than that for the angle integrated mass distribution, which should encourage the evaluation of these moments from the present measurements of the reaction.

High-energy wide-angle photoproduction of $\pi \mathrm{\Delta }$ final states is investigated within the handbag mechanism to twist-3 accuracy. In this approach the process amplitudes factorize in a hard partonic subprocess and in form factors which represent $1/x$-moments of $p-\mathrm{\Delta }$ transition generalized parton distributions (GPDs) at zero skewness. The subprocess, calculated to twist-3 accuracy, is the same as in pion photoproduction. The $p-\mathrm{\Delta }$ GPDs are related to the proton-proton GPDs exploiting large-$N_C$ results. The proton-proton GPDs as well as the twist-2 and twist-3 pion distribution amplitudes appearing in the subprocess are taken from other work. Reasonable agreement with experiment is found in this almost parameter-free analysis.

Semileptonic decays of $D$ and $D_s$ mesons into orbitally and radially excited strange and light mesons are studied in detail within the framework of the relativistic quark model based on the quasipotential approach and quantum chromodynamics. The hadronic matrix elements of the weak current between meson states are calculated with the consistent account of relativistic effects including contributions of the intermediate negative energy states and boosts of the meson wave functions from the rest to moving reference frame. The invariant form factors that parametrize these matrix elements are obtained as the overlap integrals of the initial and final meson wave functions. Their dependence on the square of the transferred momentum $q^2$ is explicitly determined within the whole accessible kinematic range. A convenient analytical approximation for numerical values of form factors is given. These form factors and helicity formalism are employed for the calculation of the differential and total semileptonic decay rates of charm mesons into excited strange and light mesons. Different asymmetry and polarization parameters are also evaluated. The obtained results are compared with other theoretical calculations and available experimental data. Reasonable agreement with experimentally measured semileptonic decay branching fractions and upper bounds is obtained.

Studying the isotopic composition of cosmic ray (CR) provides crucial insights into the galactic environment and helps improve existing propagation models. Special attention is given to the secondary-to-primary ratios of light isotopic components in CR, as these measurements can offer complementary data compared to traditional secondary-to-primary ratios like $\mathrm{B}/\mathrm{C}$. Recently, a precision measurement of the deuterium (D) abundance in CR in the 2–21 GV rigidity range provided by the AMS02 experiment unexpectedly detected an excess of D with respect to its expected secondary nature, opening the field for new measurements at high rigidity to determine how the spectrum evolves and whether there is confirmation of a primary or primary plus secondary origin. While there are theoretical models that attempt to explain this excess, the experimental uncertainties on D production cross sections and on CR propagation models remain significant, and only new and precise measurements can dissipate existing doubts. In this work, we review the current experimental scenario, and we propose a dedicated experiment that is able to extend the D abundance measurement up to $100\mathrm{GeV}/\mathrm{nucl}$ without the need of a magnetic spectrometer, using a multiple-scattering-based technique for the measurement of particle momentum. The expected performance of the proposed detector is assessed through a dedicated simulation using the geant4 package, and its role in the current particle physics scenario is discussed.

Exact solutions depending on one variable of gravitational theory with antisymmetric tensor and a coupled dilaton field are obtained in arbitrary space-time dimensions. These solutions are relevant to M theory, type IIA, and type IIB supergravity theories in various space-time signatures.