The BESIII collaboration has recently reported the first time measurement of the decay asymmetry $\alpha ({\mathrm{\Lambda }}_c^{+}\to {\mathrm{\Xi }}^0{K}^{+})=0.01\pm 0.16(\mathrm{stat})\pm 0.03(\mathrm{syst})$ and also a sizable phase shift of ${\delta }_P-{\delta }_S=-1.55\pm 0.25$ or $1.59\pm 0.25$ between S- and P-wave amplitudes. This implies significant strong phase shifts in the decay amplitudes. The strong phases indicate the existence of rescattering or loop effects, which are challenging to calculate due to nonperturbative effects. By employing the flavor $SU(3{)}_F$ symmetry and applying the Körner-Pati-Woo theorem to reduce the number of parameters, we find that the current data already allow us to obtain, for the first time, model-independent decay amplitudes and their strong phases. The establishment of the existence of sizable strong phases opens a window for future investigations into $CP$ violation. In our fit, a notable discrepancy emerges in the branching ratio of ${\mathrm{\Xi }}_c^0\to {\mathrm{\Xi }}^{-}{\pi }^{+}$. The direct relationship between $\mathrm{\Gamma }({\mathrm{\Lambda }}_c^{+}\to \mathrm{\Lambda }{e}^{+}{\nu }_e)$ and $\mathrm{\Gamma }({\mathrm{\Xi }}_c^0\to {\mathrm{\Xi }}^{-}{e}^{+}{\nu }_e)$, along with newly discovered $SU(3{)}_F$ relations, collectively suggests an underestimation of $\mathcal{B}({\mathrm{\Xi }}_c^0\to {\mathrm{\Xi }}^{-}{\pi }^{+})$ in experimental findings.

Experiments searching for weakly interacting massive particle dark matter are now detecting background events from solar neutrino-electron scattering. However, the dominant radioactive background in state-of-the-art experiments such as LZ and XENONnT is beta decays from radon contamination. In spite of careful detector material screening, radon progenitor atoms are ubiquitous and long-lived, and radon is extremely soluble in liquid xenon. We propose a change of phase and demonstrate that crystalline xenon offers more than a factor $\times 500$ exclusion against radon ingress, compared with the liquid state. This level of radon exclusion would allow crystallized versions of existing experiments to probe spin-independent cross sections near ${10}^{-47}{\mathrm{cm}}^2$ in roughly 11 years, as opposed to the 35 years required otherwise.

We provide an account of the issue of Gibbons-Hawking-York-like boundary terms for a gravity theory defined on a Riemann-Cartan spacetime. We further discuss different criteria for introducing boundary terms in some familiar first-order gravity theories with both on-shell vanishing and nonvanishing torsion, along with considerations regarding the thermodynamics of black holes and profiles of the end-of-the-world branes. Our analysis confirms the expected geodesic profile of the end-of-the-world brane in the BF formulation of Jackiw-Teitelboim gravity. Finally, we present the first realization of the AdS/BCFT duality for spacetime with torsion.

Here we study the Penrose limit of the $T$ dual of the Maldacena-Nastase solution and its field theory dual, in order to better understand the effect of $T$ duality in this case. We find a matching of string $pp$ wave oscillators and their masses to the field theory modes, that are rearranged after $T$ duality. The effect of $T$ duality on the long “annulon-type” operators is found as a symmetry of the ($2+1$)-dimensional confining theory with spontaneous supersymmetry breaking.

The definition of a particle varies across different theories. The quantum field theory in curved spacetime shows that from the perspective of a linearly accelerated observer, an inertial empty space may be full of thermal particles. This effect is known as the Unruh effect. When the degrees of freedom of orbital angular momentum (OAM) are considered, all OAM modes share the same expected particle number. Here, we examine the OAM spectrum in a rotating accelerated reference frame to see how the spectrum differs from the linear accelerated case. When the observer starts to rotate, not all OAM modes are allowed and some negative energy modes show up. To understand how a rotating accelerated observer actually perceives these particles, the Unruh-DeWitt detector and its detailed balance are studied. This relation is studied both in the comoving inertial frame and in the rest frame. Based on these results, the OAM entanglement degradation is explored in two-dimensional and high-dimensional cases, respectively. The results indicate that the entanglement dimension and the highest order of OAM modes are mainly related to the acceleration and the rotation, respectively. It is then demonstrated that these results can be generalized to all stationary trajectories.

Classically, reflectionless kinks transmit all incident radiation. Recently, we have used an analyticity argument together with a solution of the Lippmann-Schwinger equation to write down the leading quantum correction to the reflection probability. The argument was fast, but rather indirect. In the present paper, we calculate the reflection coefficient and probability by methodically grinding through the Schrödinger picture time evolution. We find the same answer. This answer contains contributions not considered in the traditional calculation of meson-kink scattering in 1991. However, as a result of these contributions, our total result is zero in the case of the Sine-Gordon model, and so it is consistent with integrability.

The perturbative consistency of coherent states within interacting quantum field theory requires them to be altered beyond the simple nonsqueezed form. Building on this point, we perform explicit construction of consistent squeezed coherent states, required by the finiteness of physical quantities at the one-loop order. Extending this analysis to two loops, we demonstrate that a non-Gaussian alteration of squeezed coherent states is necessary. The modifications of the coherent state we propose are perturbative in $\hslash$ and may be an indication that coherence must be viewed through a nonlinearly redefined, background-dependent, degree of freedom.

Angular momentum and spin precession are expected to be generic features of a significant fraction of binary black hole systems. As such, it is essential to have waveform models that faithfully incorporate the effects of precession. Here, we assess how well the current state-of-the-art models achieve this for waveform strains constructed only from the $\ell =2$ multipoles. Specifically, we conduct a survey on the faithfulness of the waveform models seobnrv5phm, teobresums, imrphenomtphm, imrphenomxphm to the numerical relativity (NR) surrogate nrsur7dq4 and to NR waveforms from the SXS catalog. The former assessment involves systems with mass ratios up to 6 and dimensionless spins up to 0.8. The latter employs 317 short and 23 long SXS waveforms. For all cases, we use reference inclinations of zero and 90°. We find that all four models become more faithful as the mass ratio approaches unity and when the merger-ringdown portion of the waveforms are excluded. We also uncover a correlation between the coprecessing $(2,\pm 2)$ multipole mismatches and the overall strain mismatch. We additionally find that for high inclinations, precessing $(2,\pm 1)$ multipoles that are more faithful than their $(2,\pm 2)$ counterparts, and comparable in magnitude, improve waveform faithfulness. As a side note, we show that use of uniformly filled parameter spaces may lead to an overestimation of precessing model faithfulness. We conclude our survey with a parameter estimation study in which we inject two precessing SXS waveforms (at low and high masses) and recover the signal with seobnrv5phm, imrphenomtphm, and imrphenomxphm. As a bonus, we present preliminary multidimensional fits to model unfaithfulness for Bayesian model selection in parameter estimation studies.

Spherical black hole (BH) solutions have been found in the bumblebee gravity where a vector field nonminimally couples to the Ricci tensor. We study dynamic (in)stability associated with the gravitational and vector perturbations of odd parity against these bumblebee BHs. Under the plane-wave approximation, we find that bumblebee BHs do not suffer ghost instability, but gradient instability and tachyonic instability exist when the bumblebee charge exceeds certain values. The existence of the instabilities also depends on the nonminimal coupling constant $\xi$ such that there is a minimal value $\xi \sim 4\pi G$ with $G$ the gravitational constant for the instabilities to happen. The theoretical consideration for bumblebee BH stability turns out to place stronger constraints on the parameter space than those from the recent observations of supermassive BH shadows by the Event Horizon Telescope Collaboration. It is also reminiscent of Penrose’s cosmic censorship conjecture since the charge of bumblebee BHs cannot be too large due to the dynamic instabilities. Specifically, for $\xi (\xi -16\pi G)>0$, we find that the charge of a bumblebee BH cannot be larger than its mass.

The measurement of the parametrized post-Newtonian parameter ${\gamma }_{\mathrm{PPN}}$ is a robust test of general relativity (GR). In some modified theories of gravity, ${\gamma }_{\mathrm{PPN}}$ may evolve with the redshift and deviate from one at high redshifts. This means that precise constraints on ${\gamma }_{\mathrm{PPN}}$ acquired in the solar system experiments could not be sufficient to test such theories and it is necessary to constrain ${\gamma }_{\mathrm{PPN}}$ with high precision at high redshifts. However, in many approaches aimed at extragalactic tests of GR, the results might be biased due to entanglement of various factors, such as cosmic curvature, cosmic opacity, and the Hubble constant. Strong lensing systems naturally provide a laboratory to test ${\gamma }_{\mathrm{PPN}}$ at galactic scales and high redshifts, but there is degeneracy between measured strength of gravity and cosmic distances in the lensing system. Gravitational waves (GWs) from binary neutron star mergers (standard sirens) provide a direct way to break this degeneracy by providing self-calibrated measurements of the luminosity distance. We investigate the possibility of estimating ${\gamma }_{\mathrm{PPN}}$ by combining well-measured strongly lensed systems with GW signals from coalescing neutron stars. Such combination provides a cosmological-model independent, relatively pure and unbiased method for the inference of ${\gamma }_{\mathrm{PPN}}$ parameter, avoiding the influence of the above factors and the mass-sheet degeneracy in the lens. Based on the simulated future 55 lensed quasar systems we demonstrated that the precision of ${\gamma }_{\mathrm{PPN}}$ parameter obtained by our method could be of order of $\sim {10}^{-2}$. One may reasonably expect that our approach will play an increasingly important role in precise testing the validity of general relativity at galactic scales and high redshifts.

We present a novel study of Kerr Compton amplitudes in a partial wave basis in terms of the Nekrasov-Shatashvili (NS) function of the confluent Heun equation (CHE). Remarkably, NS-functions enjoy analytic properties and symmetries that are naturally inherited by the Compton amplitudes. Based on this, we characterize the analytic dependence of the Compton phase shift in the Kerr spin parameter and provide a direct comparison to the standard post-Minkowskian (PM) perturbative approach within general relativity (GR). We also analyze the universal large frequency behavior of the relevant characteristic exponent of the CHE—also known as the renormalized angular momentum—and find agreement with numerical computations. Moreover, we discuss the analytic continuation in the harmonics quantum number $\ell$ of the partial wave, and show that the limit to the physical integer values commutes with the PM expansion of the observables. Finally, we obtain the contributions to the tree-level, point-particle, gravitational Compton amplitude in a covariant basis through $\mathcal{O}(a_{\mathrm{BH}}^8)$, without the need to take the superextremal limit for Kerr spin.

Relativistic jets accompany the collapse of massive stars, the merger of compact objects, or the accretion of gas in active galactic nuclei. They carry information about the central engine and generate electromagnetic radiation. No self-consistent simulations have been able to follow these jets from their birth at the black hole scale to the Newtonian dissipation phase, making the inference of central engine property through astronomical observations undetermined. We present the general relativistic moving-mesh framework to achieve the continuity of jet simulations throughout space and time. We implement the general relativistic extension for the moving-mesh relativistic hydrodynamic code, jet, and develop a tetrad formulation to utilize the Harten-Lax-van Leer Contact Riemann solver in the general relativistic moving-mesh code. The new framework is able to trace the radial movement of relativistic jets from central regions where strong gravity holds all the way to distances of jet dissipation.

A parametrized multipolar gravitational wave phasing within multipolar post-Minkowskian and post-Newtonian formalism was developed in earlier works [S. Kastha et al., Phys. Rev. D 98, 124033 (2018) and Phys. Rev. D 100, 044007 (2019)]. This facilitates the model-agnostic tests for the multipolar structure of compact binaries using gravitational wave observations. In this paper, we derive a parametrized multipolar amplitude of the gravitational wave signal in terms of mass and current-type radiative multipole moments within the post-Newtonian approximation to general relativity. We assume the compact binary to be moving in quasicircular orbits, with component spins (anti-) aligned with respect to the binary’s orbital angular momentum. We report a closed-form expression for the parametrized multipolar amplitude of the waveform at second post-Newtonian order both in time and frequency domains. This includes the contribution from the leading five mass-type and the leading four current-type radiative moments. This framework of constructing a parametrized waveform accomplishes a generic parametrization of both gravitational wave phase and amplitude with the same set of phenomenological parameters. Hence, it should significantly enhance the precision of the multipole tests in the context of present and future gravitational wave detectors.

We develop a numerical approach to compute polar parity perturbations within fully relativistic models of black hole systems embedded in generic, spherically symmetric, anisotropic fluids. We apply this framework to study gravitational wave generation and propagation from extreme mass-ratio inspirals in the presence of several astrophysically relevant dark matter models, namely the Hernquist, Navarro-Frenk-White, and Einasto profiles. We also study dark matter spike profiles obtained from a fully relativistic calculation of the adiabatic growth of a BH within the Hernquist profile, and provide a closed-form analytic fit of these profiles. Our analysis completes prior numerical work in the axial sector, yielding a fully numerical pipeline to study black hole environmental effects. We study the dependence of the fluxes on the DM halo mass and compactness. We find that, unlike the axial case, polar fluxes are not adequately described by simple gravitational-redshift effects, thus offering an exciting avenue for the study of black hole environments with gravitational waves.

In this paper we consider the motion of a rotating black hole through a static, homogeneous, massless scalar field. In the general case, a constant vector of the field gradient can be timelike, spacelike, or null. We consider and compare all of these cases. We demonstrate that as a result of the interaction of the black hole with the scalar field, its mass, spin, and relative velocity with respect to the field can change. We obtain the equations describing the evolution of these parameters and present solutions of the obtained equations for some simple cases.

We analyze the possibility of global anisotropy of the Universe. We consider an altered Friedmann Lemaitre Robertson Walker metric in which there are different scale factors along the three different axes of space. We construct the corresponding altered Friedmann equations. We show that any initial anisotropies decrease into the future. At late times, the difference in Hubble parameters changes as $1/\sqrt{t}$ in a radiation dominated era and as $1/t$ in a matter dominated era. We use constraints from big bang nucleosynthesis and the cosmic microwave background to constrain the level of anisotropies at early times. We also examine how the approach back in time to the singularity is radically altered; happening much more abruptly, as a function of density, in an anisotropic universe. We also mention improved bounds that can arise from measurements of primordial gravitons, Weakly interacting massive particles, and neutrinos.

In this study, we explore the potential of utilizing the four Minkowski functionals, which can fully describe the morphological properties of the large-scale structures, as a robust tool for investigating the modified gravity, particularly on nonlinear and quasilinear scales. With the assistance of the $N$-body simulation, we employ the Minkowski functionals to probe the Hu-Sawicki $f(R)$ gravity model. The focus is on understanding the morphological properties extracted by the Minkowski functionals and their sensitivity to modified gravity. Our analysis involves a comprehensive examination of the cosmic variance arising from finite simulation volumes. By systematically varying smoothing scales and redshifts, we quantify the information encoded in the Minkowski functionals measured from the dark-matter density field. The goal is to assess the capacity of the Minkowksi functionals to constrain the model and explore potential improvements through their combination. Additionally, we investigate the impact of using biased tracers such as dark matter halos and the halo occupation distribution galaxies on the modified gravity signatures within the Minkowksi functionals of the large-scale structures. Furthermore, we evaluate the influence of the redshift space distortion on the observed results. In summary, our study suggests that the Minkowski functionals of the large-scale structures hold promise as a stringent tool for constraining modified gravity and offer valuable insights into the morphological features of the cosmic web.

We investigate the potential of the Square Kilometre Array (SKA) in detecting synchrotron radiation emitted from the decay of sub-GeV dark matter (dark matter with masses below the GeV scale) in the presence of strong magnetic fields. As a concrete setup, we consider scenarios where the magnetosphere of a magnetic white dwarf overlaps with dense dark matter environments, such as those surrounding a primordial black hole. Our study reveals that the encounters of compact objects such as white dwarfs and black holes offer a promising avenue for upcoming radio telescopes to probe the properties of light dark matter, which has been less explored compared with more conventional heavier (masses above the GeV scale) dark matter.