A resistive magnetohydrodynamics simulation with a dynamo term is performed for modeling the collapsar in full general relativity. As an initial condition, a spinning black hole and infalling stellar matter are modeled based on a stellar evolution result, superimposing a weak toroidal magnetic field. After the growth of a massive torus around the black hole, the magnetic field is amplified in it, developing poloidal fields via dynamo. In an early stage of the torus growth, magnetic fluxes that fall to the vicinity of the central black hole are swallowed by the black hole and global poloidal magnetic fields that can be the source of the Blandford-Znajek mechanism are not developed. However, in a later stage in which the ram pressure of the infalling matter becomes weak, the magnetic field amplified by the black hole spin via the winding becomes large enough to expel the infalling matter by the magnetic pressure, and subsequently, a global poloidal magnetic field that penetrates the black hole is established, launching a jet along the spin axis by the Blandford-Znajek mechanism with the luminosity suitable for explaining typical long gamma-ray bursts. Together with the jet launch, the effectively viscous effect in the inner region of the torus and the magnetocentrifugal effect drive the stellar explosion with the explosion energy comparable to typical or powerful supernovae. We also find large amounts of synthesized ${}^{56}\mathrm{Ni}$ and Zn associated with the stellar explosion. In the presence of jet launching, $r$-process elements are weakly synthesized. The numerical results of the explosion energy, ejecta mass, and ${}^{56}\mathrm{Ni}$ mass are in a good agreement with those for observed broad-lined type Ic supernovae. Our result illustrates a self-consistent scenario for the gamma-ray-burst-associated broad-lined type Ic supernovae.

We propose a brand-new formalism for the propagation of relativistic cosmic ray (CR) particles. The propagation of CRs has often been described using the diffusion approximation, which has the drawback that the propagation speed of CRs near the source exceeds the speed of light. By applying the analytic solution of the time-dependent distribution function of photons propagating while undergoing scattering, which we recently proposed, we have succeeded in formulating the propagation of relativistic CRs while preserving causality. The obtained formulas give correct expressions both in the diffusion regime and the ballistic regime, as well as the transition between them. They can be applied to the propagation of PeV CRs around their sources (PeVatrons), the propagation of ultrahigh energy CRs, and the description of TeV gamma-ray halos around pulsars.

Light, weakly coupled bosonic particles such as axions can mediate long range monopole-dipole interactions between matter and spins. We propose a new experimental method to detect such a force exerted by the spin of electrons on a freely falling atom using atom interferometry. The intrinsic advantages of atom interferometry, such as the freely falling nature of the atom and the well-defined response of the atom to external magnetic fields, should enable the proposed method to overcome systematic effects induced by vibrations, magnetic fields, and gravity. This approach is most suited to probe forces with a range $\gtrsim 10\mathrm{cm}$. With current technology, our proposed setup could potentially extend probes of such forces by an order of magnitude beyond present laboratory limits.

Axionlike particles (ALPs) can be produced in gamma ray bursts, altering the polarization of the electromagnetic emission in these events. For the first time, we derive bounds on the axion-photon coupling from polarization measurements of GRB 221009A, performing a full calculation of the Stokes parameters, as it is typically done in the astrophysics community. Within astrophysical uncertainties, our limits on the axion-photon coupling are competitive with complementary probes in the axion mass range ${10}^{-9}\mathrm{eV}\lesssim m_a\lesssim {10}^{-8}\mathrm{eV}$, further allowing to probe motivated parameter space of ALP dark matter.

We study the discovery potential of $Z$ branching ratios due to contributions induced by the minimal supersymmetric standard model (MSSM) electroweak sector, assuming that the squarks and gluinos are heavy. Precision measurements at a future $Z$ factory would yield sensitivity to MSSM that is complementary to direct searches at the LHC, provided that the systematic uncertainties can be reduced to a level comparable to the expected statistical uncertainties.

We compute the Gross-Llewellyn Smith sum rule, i.e., the lowest odd moment of the parity-violating structure function, $F_3$, of the nucleon from a lattice QCD calculation of the Compton amplitude. Our calculations are performed on ${48}^3\times 96$ lattices at the $SU(3)$ symmetric point for two lattice spacings. We extract the moments for several values of the current momenta in the range $0.5\lesssim Q^2\lesssim 10{\mathrm{GeV}}^2$, covering both the nonperturbative and perturbative regimes. We compare our moments to the Gross-Llewellyn Smith sum rule and discuss the implications for higher-twist effects, a determination of ${\alpha }_s(Q^2)$ from a hadronic quantity complementing the phenomenological and other lattice approaches, and electroweak box contributions crucial for Cabibbo–Kobayashi–Maskawa matrix unitarity studies.

In this work, we investigate the $S$- and $P$-wave interactions of the $D{\overline{D}}^{*}$ system within the framework of the quasipotential Bethe-Salpeter equation, with the aim of exploring possible molecular states and their corresponding pole trajectories. The interaction potentials are constructed using the one-boson-exchange model, incorporating the exchanges of $\pi$, $\eta$, $\rho$, $\omega$, $\sigma$, and $J/\psi$ mesons, based on heavy quark effective Lagrangians. The poles of the scattering amplitude are analyzed and their evolution on two Riemann sheets is systematically traced as the cutoff parameter increases up to 5 GeV. We identify four molecular states arising from the $S$-wave $D{\overline{D}}^{*}$ interaction. Among them, the bound state with quantum numbers $I^G(J^{PC})=0^{+}(1^{++})$ corresponds well to the experimentally observed $X(3872)$, while its isovector partner with $I^G(J^{PC})=1^{-}(1^{++})$ is found to exist only as a virtual state. Additionally, a $0^{-}(1^{+-})$ state appears as a bound state. The isovector $1^{+-}$ state, which may be associated with the $Z_c(3900)$, is observed to evolve from a bound state to a virtual state as the interaction strength decreases. For the $P$-wave $D{\overline{D}}^{*}$ interaction, the structure $G(3900)$ recently observed at BESIII is likely connected to a $0^{-}(1^{--})$ state. A $0^{+}(0^{-+})$ state is also predicted in this channel. Both can appear as either resonance or bound/virtual state depending on the interaction strength.

This article explores particle number diffusion in relativistic hydrodynamics using kinetic theory with a modified collision kernel that incorporates the momentum dependence of the particle relaxation time. Starting from the Boltzmann equation within the extended relaxation time approximation (ERTA), we derive second-order evolution equations for the dissipative number current and calculate the associated transport coefficients. The sensitivity of transport coefficients to the particle momentum dependence of the collision timescale of the microscopic interactions in the hot QCD medium is analyzed. For a conformal, number-conserving system, we compare the ERTA-modified transport coefficients for particle diffusion with exact results derived from scalar field theory. With an appropriate parametrization of the relaxation time, we demonstrate the consistency of our analysis and assess the degree of agreement of the results with the exact solutions from scalar field theory. The relaxation times for the shear and number diffusion evolution equations are seen to be distinct in general when the momentum dependence of the relaxation time is taken into consideration.

The hadronic molecular picture of the observed exotic states has inspired numerous investigations into few-body systems. Recently, the lattice effective field theory studied the effect of a three-body interaction on the binding energy of the $D{D}^{*}K$ system, revealing an intriguing phenomenon in the binding energy. This work uses the Gaussian expansion method to explore the underlying physics. Our results show that as the repulsive three-body interaction strengthens, the spatial size of the $D{D}^{(*)}K$ bound state gradually increases. Further enhancement of the three-body interaction causes the $D{D}^{(*)}K$ three-body bound state to break into a $D^{(*)}K$ two-body bound state, accompanied by a distant $D$ meson. The identical nature of the two $D$ mesons leads to the fact that the $DDK$ system consistently resembles an isosceles triangle-shaped spatial configuration.

We introduce a novel approach to describe real-valued $m=0$ modes from inspiral to merger and ringdown in effective-one-body models, including both oscillatory and null memory contributions. A crucial aspect of the modelization of the oscillatory part is the complexification of the real modes via a Hilbert transform. This procedure allows for an accurate description of the merger-ringdown waveform by applying standard approaches employed for the complex $m>0$ modes, which include source-driven effects. The physical signal is then recovered by solely considering the real part. We apply this method in the extreme-mass-ratio regime, considering particle-driven linear gravitational perturbations in Schwarzschild and Kerr spacetimes. We then extend our description to spin-aligned, quasicircular, comparable-mass binaries providing hierarchical fits incorporating the test-mass limit. The postmerger waveform is then matched with an inspiral effective-one-body waveform. By adopting TEOBResumS-GIOTTO as our baseline, we also include the displacement memory in the (2, 0) mode through Bondi–van der Burg–Metzner-Sachs balance laws, thus providing a complete effective-one-body model incorporating both oscillatory and null memory effects. The accuracy of this model is validated against the hybrid numerical relativity surrogate NRHybSur3dq8_CCE, finding, for the quadrupole of the equal mass nonspinning case, a LIGO noise-weighted mismatch of $\overline{\mathcal{F}}=6\times {10}^{-4}$ at $50M_{\odot }$ for the inclination that maximizes the contribution of the (2, 0) mode.

The goal of the bulk reconstruction program is to construct boundary representations of fields in asymptotically anti–de Sitter spacetimes. In this paper, we extend the program by computing the boundary representation of massless fields in an Achucarro-Ortiz black hole spacetime. We obtain analytic expressions for smearing functions in both the exterior and interior of the black hole. We also obtain expressions for Papadodimas-Raju mirror operators.

Photons propagating in curved spacetime are inevitably affected by gravitational redshift, which adds additional noise to the channel for the transmission of information and decreases the precision of phase estimation of quantum states. Theoretical and experimental results demonstrate that weak measurement and quantum measurement reversal can indeed be useful for battling against decoherence. In our scheme, we employ weak measurement and quantum measurement reversal to enhance phase estimation precision for single-qubit and two-qubit systems affected by gravitational redshift in both amplitude-damping and phase-damping channels. For some quantum states, we find a direct relationship between the quantum Fisher information of phase estimation and quantum coherence. Our results show that combining weak measurement with quantum measurement reversal significantly suppresses decoherence in these channels and improves the precision of phase estimation for quantum states affected by gravitational redshift. Under the maximum measurement strength, our scheme attains optimal precision of phase estimation while eliminating the influence of gravitational redshift in both quantum channels.

Using the holographic model of the finite end point momentum shooting string approach, we study the instantaneous energy loss of light quarks for the flavor-dependent systems with $N_f=0$, $N_f=2$, and $N_f=2+1$ in the Einstein-Maxwell-dilaton framework. In particular, we investigate for the first time the impact of the flavor content of the strongly coupled quark-gluon plasma medium on the instantaneous energy loss of light quarks. It turns out that the instantaneous energy loss of light quarks is smallest for $N_f=0$, and adding $u(d)$ quarks and $s$ quark in the system increases this energy loss. In addition, we found that the instantaneous energy loss in the strongly coupled plasma is minimal near the critical temperature, but it increases as the system moves away from the critical end point due to rising temperature or chemical potential.

We perform the study of perturbative aspects of a three-dimensional supersymmetric Maxwell-Chern-Simons-Proca theory minimally coupled to scalar superfields. Using the superfield formalism, we derive the propagators for both gauge and matter superfields and compute the leading quantum corrections to the effective action. The presence of the Proca-like term explicitly breaks gauge invariance, modifying the structure of the gauge superfield propagator and leading to an essentially new form of quantum contributions in comparison with the usual QED. We analyze the Feynman diagrams that contribute to the quadratic part of the effective action, obtaining corrections to both the kinetic and mass terms of the scalar superfields. Furthermore, we discuss the UV behavior of the model, considering its renormalization properties and the possibility of perturbative finiteness to all loop orders, similar to supersymmetric ${\mathrm{QED}}_3$. Finally, we highlight potential applications of this model in condensed matter systems and possible connections with modified supersymmetric electrodynamics and dualities in lower-dimensional theories.

This paper presents a systematic exploration of exact solutions for electrically charged wormholes, black holes, and black bounces within the hybrid metric-Palatini gravity (HMPG) framework. HMPG combines features of the metric and Palatini formulations of modified gravity, offering a powerful approach to address challenges in general relativity, particularly those related to cosmic acceleration and dark matter. We examine configurations characterized by a zero scalar potential under spherical symmetry and present solutions in both the Jordan and Einstein conformal frames. A diverse set of solutions emerges, including traversable wormholes, black holes with double horizons, and “black universe” models in which spacetime beyond the horizon leads to an expanding cosmological solution rather than a singularity. Each configuration is categorized according to the properties of the scalar field, with an in-depth analysis of the horizon and throat structures, asymptotic behavior, and singularities. These findings underscore the versatility of HMPG in capturing complex gravitational phenomena and broadens the scope of the theory, offering a robust framework for modeling gravitational phenomena across a range of astrophysical contexts. Future work will benefit from extending these solutions to include scalar potentials, addressing both early-universe inflation and late-time acceleration and applying observational data, such as gravitational lensing and gravitational wave measurements.

The incompatibility of explicit diffeomorphism violation with Riemannian geometry within the gravitational Standard-Model Extension (SME) is revisited. We review two methods of how to deal with this problem. The first is based on an approach proposed originally by Stückelberg and the latter is to restrict spacetime geometry via the dynamical field equations and the second Bianchi identities. Moreover, a third technique is introduced in this work, which relies on isometries of a gravitational system. Our conclusion is that an SME background field configuration compatible with Riemannian geometry is more likely to be determined the more diffeomorphisms are isometries of the particular system. The proposal is demonstrated to work for cosmological time evolution with the SME backgrounds $u$ and $s^{\mu \nu }$ present. This finding has the potential to provide an alternative treatment of explicit spacetime symmetry violation in gravity.

We discuss new recurrence-based methods for calculating the complex frequencies of the quasinormal modes of black holes. These methods are based on the Frobenius series solutions of the differential equation describing the linearized radial perturbations. Within the general method, we propose two approaches: the first involves calculating the series coefficients, while the second employs generalized continued fractions. Moreover, as a consequence of this analysis, we present a computationally efficient and convenient method that uses double convergence acceleration, consisting of the application of the Wynn algorithm to the approximants obtained from the Hill determinants, with the Leaver-Nollert-Zhidenko-like tail approximations taken into account. The latter is particularly important for stabilizing and enabling the calculations of modes with small real parts as well as higher overtones. The method demonstrates exceptionally high accuracy. We emphasize that Gaussian elimination is unnecessary in all of these calculations. We consider $D$-dimensional ($3<D<10$) Schwarzschild-Tangherlini black holes as concrete examples. Specifically, we calculate the quasinormal modes of the ($2+1$)-dimensional acoustic black hole (which is closely related to the five-dimensional Schwarzschild-Tangherlini black holes), the electromagnetic-vector modes of the six-dimensional black holes and the scalar (gravitational tensor) modes in the seven-dimensional case. We believe that the methods presented here are applicable beyond the examples shown, also outside the domain of the black hole physics.

Some black hole mimickers, as well as black strings and other higher-dimensional spacetimes, exhibit stable light rings-regions where light or high-frequency gravitational waves can be trapped. In these regions, linear perturbations decay slowly, raising the possibility of nonlinear instability mechanisms. In this work, we study the cubic nonlinear wave equation as a proxy for Einstein’s equations, using a four-dimensional model geometry that allows stable trapping. By employing a perturbative approach, and neglecting the backreaction onto the spacetime, we show that the nonlinear wave equation on the sphere with dissipative terms captures several features of the full nonlinear problem. This framework allows us to confirm a previous conjecture: all higher-order energy norms grow for arbitrarily small initial fluctuation amplitudes. Additionally, we analyze the system’s mode spectrum at late times, revealing an inertial range dominated by a direct energy cascade. These findings further support the notion that spacetimes with stable light rings develop weak, high-frequency radiation hair, which will not generically lead to instabilities.

We explore cosmological particle production associated with inflationary fluctuations by comparing gravitational and geometric mechanisms, within a nonminimal Yukawa-like coupling between a inflaton and spacetime curvature. We show under which circumstances the number of geometric particles is comparable to the purely gravitational contribution by introducing the S-matrix formalism and approximating the inflationary potentials through power series. Despite the geometric production is a second-order effect, we show that it cannot be neglected a priori, emphasizing that throughout inflation we do expect geometric particles to form as well as in the reheating phase. This result is investigated in both the Jordan and Einstein frames, selecting inflationary potentials supported by the Planck Satellite outcomes, i.e., the Starobinsky, hilltop, $\alpha$-attractor, and natural inflationary paradigms. We notice that, for large field approaches, the only feasible coupling may occur in case of extremely small field-curvature coupling constants, while the small field frameworks, namely the hilltop and $\alpha$-attractor models with quartic behavior, are essentially ruled out since they do not appear dynamically viable. We then point out that, while dynamically there exists a net equivalence between the Jordan and Einstein frames, the number of particles appears quite different passing from a representation to another one, thus pointing out the existence of a possible quantum frame issue that persists even in the limit of small coupling constants $\xi \simeq {10}^{-4}$, for which other inflationary observables such as the spectral index and the tensor-to-scalar ratio were shown to coincide in previous literature. In summary, while the classical inflationary dynamics is equivalently described in the Jordan and Einstein frames, a viable physical description of particle production valid in both the frames may be hindered by the absence of a complete quantum gravity. The latter could therefore be seen as missing puzzle to address the longstanding challenge of consistently passing between the two frames.

In its second data release (DR2), the Dark Energy Spectroscopic Instrument (DESI) publicly released measurements of baryon acoustic oscillations (BAO) from over 13.1 million galaxies and 1.6 million quasars, covering the redshift range $0.295\le z\le 2.330$. In this work, we investigate the impact of this new dataset on dark sector interaction models, which are motivated by nongravitational interactions between dark energy (DE) and dark matter (DM), commonly referred to as interacting dark energy models (IDE). We focus on two frameworks: the traditional IDE model and the recently proposed sign-switching interacting model (S-IDE), aiming to derive new and robust constraints on both scenarios. After carefully selecting the sample for the joint analysis, ensuring compatibility among the data without significant tension, our main results indicate that both models can alleviate the $H_0$ tension, reducing it to moderate tension approximately $2.7\sigma$. The IDE model shows compatibility with the latest $S_8$ constraints from cosmic shear surveys, while the S-IDE model predicts lower values of $S_8$, which align with alternative perspectives on the $S_8$ tension. For the traditional IDE model, we derive new bounds for the coupling parameter, marking the strongest constraints to date through geometric measurements. This highlights the crucial role that supernova samples can play in refining these constraints. For the S-IDE model, we find mild evidence (over $2\sigma$) for a nonzero coupling, once the PantheonPlus dataset calibrated with Cepheid-based magnitude measurements is included in the analysis.