Utilizing various astrophysical constraints on neutron-star structures, we carry out a Bayesian analysis of the density-dependent behaviors of coupling constants in relativistic-mean-field (RMF) models as well as the nuclear matter properties at supranuclear densities. The effective nucleon interactions in the isoscalar-scalar, isoscalar-vector, and isovector-vector channels are considered, where the corresponding coupling constants (${\alpha }_S,{\alpha }_V,{\alpha }_{TV}$) are fixed by dividing the entire density range into three regions with six independent parameters. In this work, we focus on constraining the density-dependent point-coupling constants at supranuclear densities, while the coupling constants at subsaturation densities are derived from the covariant density functional DD-ME2. For those consistent with astrophysical observations, the coupling constants generally decrease with density and approach small positive values at large enough densities, which qualitatively agrees with various RMF models. The posterior probability density functions and their correlations of the coupling constants and various nuclear matter properties are examined as well. At the $1\sigma$ level, the constrained coupling constants at density $1.5n_0$ ($2.5n_0$) are ${\alpha }_S={3.1}_{-0.05}^{+0.1}(1.55_{-0.2}^{+0.85})\times {10}^{-4}{\mathrm{MeV}}^{-2}$, ${\alpha }_V={2.3}_{-0.0}^{+0.1}({1.3}_{-0.1}^{+0.55})\times {10}^{-4}{\mathrm{MeV}}^{-2}$, and ${\alpha }_{TV}=2.05_{-0.4}^{+0}(2.05_{-0.5}^{+0})\times {10}^{-5}{\mathrm{MeV}}^{-2}$. At larger densities, we find the lower limit of ${\alpha }_{TV}$ is not well constrained, so that more extensive calculations with a larger number of free parameters are necessary. Finally, the constrained pressure of neutron-star matter and symmetry energy of nuclear matter at $1.5n_0$ ($2.5n_0$) are $P=10_{-0.0}^{+0.0}$ $({60}_{-20}^{+15})\mathrm{MeV}/{\mathrm{fm}}^3$ and ${\epsilon }_{\mathrm{sym}}=45_{-3.0}^{+1.0}$ $({60}_{-6.0}^{+8.0})\mathrm{MeV}$, respectively.

In a previous work, we have shown that the data presented by the two long-baseline accelerator experiments NOvA and T2K at the Neutrino 2020 conference displayed a tension and that it could be alleviated by nonstandard neutrino interactions (NSI) of the flavor changing type involving the $e-\mu$ or the $e-\tau$ sectors with couplings $|{ϵ}_{e\mu }|\sim |{ϵ}_{e\tau }|\sim 0.1$. As a consequence, a hint in favor of NSI emerged. In the present paper, we reassess the issue in light of the new data released by the two experiments at the Neutrino 2024 conference. We find that the tension in the determination of the standard $CP$-phase ${\delta }_{\mathrm{CP}}$ extracted by the two experiments in the normal neutrino mass ordering persists and has a statistical significance of $\sim 2\sigma$. Concerning the NSI, we find that including their effects in the fit, the two values of ${\delta }_{\mathrm{CP}}$ preferred by NOvA and T2K return in very good agreement. The current statistical significance of the hint of nonzero NSI is $\sim 1.8\sigma$. Further experimental data are needed in order to settle the issue.

We present a search for the baryon number $B$ and lepton number $L$ violating decays ${\tau }^{-}\to \mathrm{\Lambda }{\pi }^{-}$ and ${\tau }^{-}\to \overline{\mathrm{\Lambda }}{\pi }^{-}$ produced from the $e^{+}{e}^{-}\to {\tau }^{+}{\tau }^{-}$ process, using a $364{\mathrm{fb}}^{-1}$ data sample collected by the Belle II experiment at the SuperKEKB collider. No evidence of signal is found in either decay mode, which have $|\mathrm{\Delta }(B-L)|$ equal to 2 and 0, respectively. Upper limits at 90% credibility level on the branching fractions of ${\tau }^{-}\to \mathrm{\Lambda }{\pi }^{-}$ and ${\tau }^{-}\to \overline{\mathrm{\Lambda }}{\pi }^{-}$ are determined to be $4.7\times {10}^{-8}$ and $4.3\times {10}^{-8}$, respectively.

We propose a new framework for computing three-point functions in planar $\mathcal{N}=4$ super Yang-Mills theory where these correlators take the form of multiple integrals of separation of variables type. We test this formalism at weak coupling at leading and next-to-leading orders in a noncompact SL(2) sector of the theory and all the way to next-to-next-to-leading orders for a compact SU(2) sector. We find evidence that wrapping effects can also be incorporated.

We analyze the real-time dynamics of the large $N$ vector model, focusing on heavy states with energies of the order $N$. In this regime, we demonstrate that interactions become sufficiently strong to produce nonzero condensate of the Hubbard-Stratonovich field $\sigma$, which, in turn, induces particle production. This process leads to a significant transformation of the initial state and potential thermalization. For homogeneous perturbations, our results show that the equations become integrable, yet can still lead to thermalization in the continuum limit. Furthermore, we calculate the energies of these heavy states and their contributions to the thermal free energy, thereby determining the free energy of the critical $O(N)$ model by operator counting.

Gaussian process regression, kernel support vector regression, the random forest, extreme gradient boosting, and the generalized linear model algorithms are applied to data of complete intersection Calabi-Yau threefolds. It is shown that Gaussian process regression is the most suitable for learning the Hodge number $h^{2,1}$ in terms of $h^{1,1}$. The performance of this regression algorithm is such that the Pearson correlation coefficient for the validation set is $R^2=0.9999999995$ with a root mean square error $RMSE=0.0002895011$. As for the train set, these two parameters are as follows: $R^2=0.9999999994$ and $RMSE=0.0002854348$. The training error and the cross-validation error of this regression are $1\times {10}^{-9}$ and $1.28\times {10}^{-7}$, respectively. Learning the Hodge number $h^{1,1}$ in terms of $h^{2,1}$ yields $R^2=1.000000$ and $RMSE=7.395731\times {10}^{-5}$ for the validation set of the Gaussian process regression.

We compute the celestial correlators corresponding to tree-level 5-gluon amplitudes in the type I superstring theory. Since celestial correlation functions are obtained by integrating over the full range of energies, there is no obvious analog of the ${\alpha }^{\prime }\to 0$ limit in this basis. This is manifestly shown by a factorization of the ${\alpha }^{\prime }$ dependence in the celestial string amplitudes. Consequently, the question arises as to how the field theory limit is recovered from string theory in the celestial basis. This problem has been addressed in the literature for the case of 4-gluon amplitudes at tree level, where the forward scattering limit of the stringy factor was identified as a limit in which celestial Yang-Mills 4-point function is recovered. Here, we extend the analysis to the case with five gluons, for which the string moduli space allows for more types of limits, thus allowing us to investigate this aspect in more detail. Based on celestial data only, we study the regime in which one arrives at the correct celestial field theory limit. We also study other properties of the celestial string amplitudes, namely, the conformally soft theorem, effective field theory expansion in the conformal basis, and a map that arises in the regime of high-energy/large-scaling dimension that connects the punctured string world sheet to the insertion of primary operators in the celestial CFT for the massless $n$-point string amplitude.

A comprehensive symmetry resolution of the entanglement entropy in ($1+1$)-d rational conformal field theories with categorical noninvertible symmetries is presented. This amounts to symmetry resolving the entanglement with respect to the generalized twisted and anyonic charged sectors of the theory. The anyonic sectors label the irreducible representations of a modular fusion category defining the symmetry and can be understood through the ($2+1$)-d symmetry topological field theory that encodes the symmetry features of the conformal field theory. Using this, we define the corresponding generalized boundary-dependent charged moments necessary for the symmetry resolution of the entanglement entropy and find that, contrary to the case of invertible symmetries, the entanglement equipartition between different charged sectors at the next-to-leading order in the ultraviolet cutoff, is broken.

We review the physical meaning of modular invariance for unitary conformal quantum field theories in $d=2$. For quantum field theory models, while $T$ invariance is necessary for locality, $S$ invariance is not mandatory. $S$ invariance is a form of completeness of the theory that has a precise meaning as Haag duality for arbitrary multi-interval regions. We present a mathematical proof as well as derive this result from a physical standpoint using Renyi entropies and the replica trick. For rational conformal field theories (CFTs), the failure of modular invariance or Haag duality can be measured by an index, related to the quantum dimensions of the model. We show how to compute this index from the modular transformation matrices. The index also appears in a limit of the Renyi mutual information. Cases of infinite index are briefly discussed. Part of the argument can be extended to higher dimensions, where the lack of completeness can also be diagnosed using the CFT data through the thermal partition function and measured by an index.

We study the backreaction of a quantum scalar field on anti–de Sitter (AdS) spacetime. The renormalized expectation value of the stress-energy tensor operator for a massless, conformally coupled quantum scalar field on global AdS spacetime in four space-time dimensions acts as a source term on the right-hand side of the Einstein equations for the quantum-corrected metric. We solve the quantum-corrected Einstein equations numerically and find deviations from pure AdS which increase as the temperature of the quantum scalar field state increases. We interpret these quantum-corrected metrics as asymptotically AdS solitons, and study the mass of these solitons as a function of the temperature of the quantum scalar field.

We investigate the response function of an inertial Unruh-deWitt detector in an impulsive plane wave spacetime. Through symmetry considerations applied to the Wightman function, we demonstrate that the response function remains invariant for any inertial detector, even for those experiencing a discontinuous light cone coordinate shift after interacting with the shock wave. This implies that the vacuum state in an impulsive plane wave spacetime is preserved under the associated spacetime symmetries. Additionally, we confirm that the quantum imprint of the shock wave, as discussed in Gray et al. [J. High Energy Phys. 11 (2021) 054], is not an artifact and exhibits a distinct characteristic form. We identify this form by defining a “renormalized” response function for an eternally inertial detector, with Minkowski spacetime as a reference.

We study a parametric deformation of the unified genus-1 anharmonic potential and derive a parametric form of perturbative/nonperturbative (P/NP) relation, applicable across all parameter values. We explicitly demonstrate that the perturbative expansion around the perturbative saddle is sufficient to generate all the nonperturbative information in these systems. Our results confirm the known results in the literature, where the cubic and quartic anharmonic potentials are reproduced under extreme parameter values, and go beyond these known results by developing the nonperturbative function of real and complex instantons solely from perturbative data.

We investigate a coupled system consisting of a complex scalar field, a U(1) gauge field, a complex Higgs scalar field, and Einstein gravity. We present nontopological soliton star solutions in which the interior geometry is described by the de Sitter metric, the exterior by the Schwarzschild metric, and these two regions are attached by a spherical surface layer with a finite thickness. This structure is the same as the so-called gravastars, so we refer to these solutions as “solitonic gravastars.” We demonstrate that compact solitonic gravastars that possessing photon spheres can appear. Additionally, we study the mass and compactness of solitonic gravastars for various sets of parameters that characterize the system.

The generalized second law states the total entropy of any closed system as the Universe cannot decrease if we include black hole entropy. From the point of view of an asymptotic observer, a black hole can be described at late time as an open system at fixed temperature which can radiate energy and entropy to infinity. I argue that for massless free quantum fields propagating on a black hole background, we can define a black hole dynamical free energy using observables defined at future null infinity which decreases on the successive cross sections of ${\mathcal{I}}^{+}$. The proof of this spontaneous evolution law is similar to Wall’s derivation of the generalized second law and relies on the monotonicity properties of the relative entropy. I discuss first the simpler case of the Schwarzschild background in which the gray body factors are neglected and show that in this case the free energy only depends on the Bondi mass, the Hawking temperature and the von Neumann entropy of the propagating quantum fields. Then I argue that taking into account the gray body factors adds a new term to the thermodynamic potential involving the number of particles detected at ${\mathcal{I}}^{+}$ conjugated to a chemical potential. Finally, I discuss the case of the Kerr black hole for which an angular momentum piece needs to be added to the free energy.

New covariant theories of emergent modified gravity exist not only in spherically symmetric models, as previously found, but also in polarized Gowdy systems that have a local propagating degree of freedom. Several explicit versions are derived here, depending on various modification functions. These models do not have instabilities from higher time derivatives, and a large subset is compatible with gravitational waves and minimally coupled massless matter fields traveling at the same speed. Interpreted as models of loop quantum gravity, covariant Hamiltonian constraints derived from the covariance conditions found in polarized Gowdy systems are more restricted than those in spherical symmetry, requiring new forms of holonomy modifications with an anisotropy dependence that has not been considered before. Assuming homogeneous space, the models provide access to the full anisotropy parameters of modified Bianchi I dynamics, in which case different fates of the classical singularity are realized depending on the specific class of modifications.

We study the constraints on primordial magnetic fields (PMFs) in light of the global 21-cm signal observed during the dark ages. Primordial magnetic fields can heat the intergalactic medium (IGM) via magnetohydrodynamic effects. We investigate the impact of magnetic heating on the dark ages global 21-cm signal and constrain the present-day strength of primordial magnetic fields and their spectral indices. Since there were no stars during the dark ages, measuring the global 21-cm signal can provide pristine cosmological information. However, detecting this signal using ground-based telescopes is challenging. Several lunar and space-based experiments, such as FARSIDE, DAPPER, and FarView, have been proposed to detect the signal in future. Our findings indicate that measuring the 21-cm global signal during the dark ages can provide stronger bounds compared to the existing constraints from Planck 2016. Specifically, the bounds are independent of astrophysical uncertainties and stronger for spectral indices $-2.84\le n_B\le -1.58$. Additionally, we explore the dark-ages consistency ratio, which can identify any nonstandard heating of the IGM by measuring the 21-cm signal at only three different redshifts. This approach could complement future experiments aimed at detecting the dark ages global 21-cm signal.

In the first-order phase transitions (PTs) colliding bubble is an important gravitational wave (GW) source. Following bubble collision, domain walls can be formed when degenerate vacua occur as a result of the spontaneous breaking of a discrete symmetry relevant to new physics at electroweak or higher scales. Using lattice simulations, we study the dynamical evolution of domain walls and find that the networks of the domain wall are formed around the completion of PTs and quickly collapse before entering into the scaling regime provide that the degeneracy of true vacua is broken. Our numerical results indicate that domain wall networks continue to produce GWs in the aftermath of PTs, leading to dramatically changing the spectral shape and enhancing the magnitude by about one order. The resulting GW power spectra are peaked at $k{R}_{*}\simeq \pi$ as predicted by the envelop approximation model, above the peak wave number it has a decaying power law close to $k^{-1.2}$ followed by a slowly decreasing plateau with the UV cutoff at $k{R}_{*}\sim \mathcal{O}({10}^2)$.

In this article we calculate the reheating temperature in the cosmological scenarios where heavy scalar particles are gravitationally produced, due to a conformally coupled interaction between a massive scalar quantum field and the Ricci scalar, during the oscillations of the inflaton field. We explore two distinct cases, namely the one in which these particles decay during the domination of the inflaton’s energy density and the other one where the decay occurs after this phase. For each scenario, we have derived formulas to calculate the reheating temperatures based on the energy density of the produced particles and their decay rate. We establish bounds for the maximum reheating temperature, defined as the temperature reached by the universe when the decay of gravitationally produced particles concludes at the onset of the radiation-dominated epoch. Finally, we use the Born approximation to find analytic formulas for the reheating temperature.

Various gravity theories beyond general relativity have been rigorously investigated in the literature such as Horndeski and degenerate higher-order scalar-tensor (DHOST) theories. In general, numerous model parameters are involved in such theories, which should be constrained to test the theories with experiments and observations. We construct the kurtosis consistency relations, calculated based on matter density fluctuations, in which the information of gravity theories is encoded. We derive two independent consistency relations that should hold in the framework of the DHOST theories and argue that such consistency relations would be useful for testing gravity theories.

In this work, we implement Gaussian process regression to reconstruct the expansion history of the Universe in a model-agnostic manner, using the Pantheon-Plus SN-Ia compilation in combination with two different BAO measurements (SDSS-IV and DESI DR1). In both the reconstructions, the $\mathrm{\Lambda }\mathrm{CDM}$ model is always included in the 95% confidence levels. We find evidence that the DESI LRG data at $z_{\mathrm{eff}}=0.51$ is not an outlier within our model-independent framework. We study the $\mathcal{O}m$ diagnostics and the evolution of the total equation of state (EOS) of our Universe, which hint toward the possibility of a quintessence-like dark energy scenario with a very slowly varying EOS and a phantom crossing in higher $z$. The entire exercise is later complemented by considering two more SN-Ia compilations—DES-5YR and Union3—in combination with DESI BAO. Reconstruction with the DESI BAO + DES-5YR SN datasets predicts that the $\mathrm{\Lambda }\mathrm{CDM}$ model lies outside the $3\sigma$ confidence intervals, whereas with DESI BAO + Union3 data, the $\mathrm{\Lambda }\mathrm{CDM}$ model is always included within $1\sigma$. We also report constraints on $H_0{r}_d$ from our model-agnostic analysis, independent of the pre-recombination physics. Our results point toward an $\approx 2\sigma$ discrepancy between the DESI + Pantheon-Plus and DESI + DES-5YR datasets, which calls for further investigation.