It has recently been revealed that charged scalar clouds, spatially regular matter configurations which are made of linearized charged massive scalar fields, can be supported by spinning and charged Kerr-Newman black holes. Using analytical techniques, we establish a no-short hair theorem for these stationary bound-state field configurations. In particular, we prove that the effective proper lengths of the supported charged massive scalar clouds are bounded from below by the remarkably compact dimensionless relation $\ell /M>\ln (3+\sqrt{8})$, where $M$ is the mass of the central supporting black hole. Intriguingly, this lower bound is universal in the sense that it is valid for all Kerr-Newman black-hole spacetimes [that is, in the entire regime $\{a/M\in (0,1],Q/M\in [0,1)\}$ of the dimensionless spin and charge parameters that characterize the central supporting black holes] and for all values of the physical parameters (electric charge $q$, proper mass $\mu$, and angular harmonic indexes $\{l,m\}$) that characterize the supported stationary bound-state scalar fields.

We investigate general relativistic effects on the photon spectrum emitted from decaying (or annihilating) particle dark matter in the halo surrounding a primordial black hole. The spectrum undergoes significant modification due to gravitational redshifts, which induces broadening as a result of the intense gravitational field near the black hole. This characteristic alteration in the photon spectrum presents a unique observational signature. Future observations of such spectral features may provide critical evidence for a mixed dark matter scenario, involving both primordial black holes and particle dark matter.

Axion-like particles (ALPs) can be copiously produced in binary neutron star (BNS) mergers through nucleon-nucleon bremsstrahlung if the ALP-nucleon couplings $g_{aN}$ are sizable. The ALP-photon coupling $g_{a\gamma }$ may trigger conversions of ultralight ALPs into photons in the magnetic fields of the merger remnant and of the Milky Way. This effect would lead to a potentially observable short gamma-ray signal, in coincidence with the gravitational-wave signal produced during the merging process. This event could be detected through multimessenger observation of BNS mergers employing the synergy between gravitational-wave detectors and gamma-ray telescopes. Here, we study the sensitivity of current and proposed MeV gamma-ray experiments to detect such a signal. As an explicit example, we consider ALP couplings related as in the Kim-Shifman-Vainshtein-Zakharov axion model, and show that in this case the proposed instruments can reach a sensitivity down to $g_{a\gamma }\gtrsim \mathrm{few}\times {10}^{-13}{\mathrm{GeV}}^{-1}$ for $m_a\lesssim {10}^{-9}\mathrm{eV}$, comparable with the SN 1987A limit.

We propose a new dark-matter detection strategy that will potentially enable the search for super-light dark matter $m_{\chi }\simeq 0.1\mathrm{keV}$, improving the minimum detectable mass by more than 3 orders of magnitude compared to ongoing experiments. This can be achieved by intimately integrating the target material, specifically the $\pi$-bond electrons in graphene, into a Josephson junction to create a highly sensitive detector capable of detecting energy deposits from dark matter as small as $\sim 0.1\mathrm{meV}$. We investigate detection prospects of pg-, ng-, and $\mathrm{\mu }\mathrm{g}\text{−}\mathrm{scale}$ detectors by calculating the scattering rate between dark matter and free electrons confined in two-dimensional graphene, including Pauli-blocking factors and in-medium screening effects. We find that the proposed detector is expected to not only serve as a complementary probe of superlight dark matter but also achieve higher experimental sensitivities than other proposed experiments, assuming zero readout noise, thanks to the extremely low threshold energy of our graphene Josephson junction sensor.

The transition from a false vacuum to the true vacuum is a real-time phenomenon of interest in many contexts. It represents a special challenge for strongly interacting non-Abelian gauge theories because standard spacetime lattices incorporate imaginary time from the outset. To attain real-time phenomena, Hamiltonian lattice methods are being developed for quantum computers. The present work considers SU(2) gauge theory on a minimal lattice in three spatial dimensions, where round-the-world strings called torelons can travel and interact. This minimal 3D lattice has a triamond structure whose properties are elucidated by calculating the spectrum of torelon states. Then, by introducing a twisted boundary condition, real-time evolution is used to demonstrate the decay of a false vacuum. Calculations in the present work are done on classical computers except for one benchmark study of imaginary time evolution that ran on the ibm_brisbane quantum computer.

Lattice QCD calculations of inclusive semileptonic decay rates involve new types of systematic effects, such as truncation errors in the estimation of energy integrals, or finite-volume effects for multibody final states. We investigate them for the lattice data of $D_s\to X_s\ell \nu$ decays, obtained using Möbius domain-wall fermions. Separating the ground-state and excited-state contributions results in better control over these systematic effects. With the Chebyshev polynomial approximation, the truncation error is under control, while the finite-volume effects are estimated using a model to describe two-body final states.

Given that the wave function of a proton can be derived relativistically and nonperturbatively from a light-front quantized Hamiltonian, investigating the quantum correlation between quarks and gluons offers a novel perspective on the internal structure of partons within a proton. In this work, we address this topic by computing the spin and longitudinal momentum entanglement of each parton inside the proton. The utilized wave functions are generated using basis light-front quantization (BLFQ), incorporating both the valence quarks and one dynamical gluon Fock sectors, $|qqq⟩$ and $|qqq⟩+|qqqg⟩$. Our calculations indicate that the dynamical gluon significantly enhances entanglement among the proton’s partons. Additionally, we examine the spin entanglement of quarks and gluons at fixed values of longitudinal momentum fraction, revealing that the presence of a gluon may amplify the informational exchanges between quarks. Finally, these findings suggest the potential for experimental verification of the entanglement between partons by measuring parton helicity distributions in the proton.

The mass and current coupling of the tensor hybrid charmonia $H_{\mathrm{c}}$ and ${\tilde{H}}_{\mathrm{c}}$ with quantum numbers $J^{\mathrm{PC}}=2^{-+}$ and $2^{++}$, as well as their full widths, are calculated in the context of the QCD sum rule method. The spectral parameters of these states are computed using the QCD two-point sum rule approach including dimension-12 terms $\sim ⟨g_s^3{G}^3{⟩}^2$. The full decay widths of the charmonia $H_{\mathrm{c}}$ and ${\tilde{H}}_{\mathrm{c}}$ are evaluated by considering their kinematically allowed decay channels. In the case of the hybrid state $H_{\mathrm{c}}$, decays to $D^{(\pm )}{D}^{*(\mp )}$, $D^0{\overline{D}}^{*0}$, and $D_s^{(\pm )}{D}_s^{*(\mp )}$ mesons are taken into account. The processes ${\tilde{H}}_{\mathrm{c}}\to D^{(*)+}{D}^{(*)-}$, $D^{(*)0}{\overline{D}}^{(*)0}$, and $D_s^{(*)+}{D}_s^{(*)-}$ are employed to estimate the full width of the hybrid charmonium ${\tilde{H}}_{\mathrm{c}}$. The partial widths of these decays are computed by means of the QCD three-point sum rule method, which is necessary to calculate strong couplings at the relevant hybrid-meson-meson vertices. Our predictions $m=(4.16\pm 0.14)\mathrm{GeV}$ and $\tilde{m}=(4.5\pm 0.1)\mathrm{GeV}$ for the masses and $\mathrm{\Gamma }[H_{\mathrm{c}}]=(160\pm 30)\mathrm{MeV}$ and $\mathrm{\Gamma }[{\tilde{H}}_{\mathrm{c}}]=(206\pm 33)\mathrm{MeV}$ for the full width of these hybrid charmonia can be useful to study and interpret various resonances in the 4–5 GeV mass range.

We investigate the heavy-quark corner of the Columbia plot using the gluon potential derived from the Curci-Ferrari extension of the Faddeev-Popov gauge fixing in the center-symmetric Landau gauge, as a proxy for the Polyakov loop potential. In line with the observation that Landau gauge couplings are not that large in the case of heavy-quark QCD, we consider a one-loop approximation and test its consistency by using various renormalization schemes while investigating the dependence of our results on the renormalization scale. We find that the main qualitative features of the phase structure in the heavy-quark regime are reproduced. Notably, we have direct access to real chemical potentials, and have tested that extrapolations from imaginary chemical potentials approximate the direct calculation well until large chemical potentials. Our results agree quantitatively with those of simulations to 10% accuracy, which is the expected precision of the one-loop calculations in applications of the Curci-Ferrari model to Yang-Mills or heavy-quark QCD theories.

We discuss prompt production of $J/\psi$ mesons in proton-proton collisions at the $\sqrt{s}=68.5\mathrm{GeV}$ energy within the nonrelativistic quantum chromodynamics $k_t$-factorization approach using different unintegrated gluon distribution functions (UGDFs). We include both direct color-singlet production ($gg\to J/\psi g$) as well as a feed-down from ${\chi }_c\to J/\psi \gamma$ and ${\psi }^{\prime }\to J/\psi X$ decays. The production of the decaying mesons ${\chi }_c$ or ${\psi }^{\prime }$ is also calculated within the nonrelativistic quantum chromodynamics $k_t$-factorization approach. Differential distributions in the rapidity and transverse momentum of $J/\psi$ are calculated and compared with experimental data of LHCb collaboration. The LHCb fixed target data allow us to test UGDFs in a new range of $x$.

We construct, for the first time, a three family $\mathcal{N}=1$ supersymmetric Pati-Salam model from rigid intersecting D6-branes on a factorizable ${\mathbb{T}}^6/({\mathbb{Z}}_2\times {\mathbb{Z}}_2^{\prime })$ orientifold with discrete torsion. The factorizable geometry allows for explicit control over rigid cycles and moduli stabilization. We can break the Pati-Salam gauge symmetry down to the Standard Model (SM) gauge symmetry via the supersymmetry preserving Higgs mechanism, generate the SM fermion masses and mixings, and break the supersymmetry via gaugino condensations in the hidden sector.

We directly evaluate the probability amplitudes in Jackiw-Teitelboim (JT) gravity using the Lorentzian path integral formulation. By imposing boundary conditions on the scale factor and the dilaton field, the Lorentzian path integral uniquely yields the probability amplitude without contradiction. Under Dirichlet boundary conditions, we demonstrate that the amplitude derived from the Lorentzian path integral is expressed in terms of the modified Bessel function of the second kind. Furthermore, we provide the determinant for various boundary conditions and perform a detailed analysis of the Lefschetz thimble structure and saddle points. In contrast to four-dimensional gravity, we show that the Hartle-Hawking no-boundary proposal is approximately valid in JT quantum cosmology. Furthermore, addressing quantum perturbation issues, we show that the quantum genesis of the two-dimensional universe occurs and exhibits perturbative regularity when the dilaton field is nonzero and large as an initial condition.

In this paper, we explore the scalar, electromagnetic, and gravitational perturbations of a Schwarzschild black hole embedded within a Dehnen-(1, 4, $\gamma$) dark matter halo. We focus on three distinct values of $\gamma$, each yielding a unique central behavior for the dark matter distribution: $\gamma =1$, where the central density vanishes; $\gamma =0$, where it remains finite; and $\gamma =1$, where it diverges. Employing higher-order Wentzel-Kramers-Brillouin and asymptotic iteration methods, we calculate the characteristic oscillation frequencies, namely, the quasinormal modes and present their temporal evolution using a time-domain approach. Our findings indicate that dark matter amplifies the gravitational pull of the black hole. While it reduces the actual oscillation frequencies of the perturbations, its impact on the damping rates of the fundamental modes is negligible. However, in the nonfundamental modes, both the real and imaginary parts of the quasinormal frequencies exhibit a pronounced decay.

The Schwarzschild solution describes a classical static black hole in general relativity. When general relativity is extended by including semiclassical corrections in the form of a renormalized energy-momentum tensor, the horizon of the Schwarzschild black hole disappears and is replaced by a wormhole. We study the stability of this quantum corrected static Schwarzschild solution in semiclassical gravity by using it as the initial data of a dynamical evolution. We find that the quantum corrected solution is unstable and that the wormhole can expand or collapse when perturbed. In vacuum, the wormhole expands, but in the presence of even a small amount of classical matter, the wormhole collapses, forming a horizon and evolving to an evaporating black hole.

Correspondences between apparently distant concepts are ubiquitous in theoretical physics. In the context of black holes (BHs), quasinormal modes (QNMs) were shown to be linked to both shadows, in the so-called eikonal limit, and graybody factors (GBFs), using the WKB approximation. We test the accuracy of the QNM-GBF correspondence in the context of the Hawking radiation for static and rotating black hole configurations, with particular attention to the superradiant regime. Our analysis reveals the correspondence failure to accurately reproduce the Hawking spectrum due to divergences. Furthermore, we bridge the gap between BH shadows and GBFs by drawing a correspondence between such quantities in the case of generic static and spherically symmetric spacetime configurations. The shadow-GBF correspondence is tested for some case studies, including regular BHs, and its limitations and applicability are discussed. This study opens new perspectives by introducing a new correspondence and remarking on the caution needed when considering these connections.

The leading-order gravitational time delay of relativistic neutral massive particles (e.g., neutrinos or high-energy cosmic-ray particles) caused by a moving Schwarzschild black hole with a constant radial velocity is investigated for the first time. On the basis of the equations of motion in the spacetime of the moving lens, we achieve a new unified formula for the travel times of relativistic massive and massless particles propagating from the source to the observer within the first post-Minkowskian approximation. The analytical form of the difference between the travel times of a relativistic massive particle and a light signal in this geometry, as well as that of two relativistic massive particles, is thus obtained in the weak-field and slow-motion limit. The influence of the radial lens motion on the leading-order Schwarzschild time delay of relativistic massive particles is then discussed. It is found that in the slow-motion limit, the radial lens motion toward the observer decreases the flight time of an ultrarelativistic massive particle, when compared with the case of no translational motion of the central body. Conversely, if the lens gets away from the detector radially under the same conditions, the propagation process of the particle will slow down and its flight time will thus increase in comparison with the Schwarzschild case. Finally, we analyze the magnitude of the full radial motion effect of the lens and evaluate the possibility of its astronomical detection by modeling three typical black holes as the lens respectively.

Renormalization of physical quantities for quantum field theories in curved spacetimes can be achieved via the subtraction of counterterms in a consistent manner within a regularization scheme such as a point-splitting method. Pragmatic mode-sum regularization (PMR) is a point-splitting method which is particularly suitable for rotating black hole spacetimes. We extend and tailor the $t$-splitting variant of PMR specifically for the interior of a Kerr black hole on the axis of rotation, focusing on a minimally coupled massless scalar field in the physically motivated Unruh state. The method addresses unique challenges within the black hole interior that do not occur outside. In particular, while the infinite sum over multipolar number $l$ converges in the black hole exterior, it diverges in the interior, necessitating the subtraction of a so-called intermediate divergence which includes introducing an additional “small” split in the direction of the polar angle $\theta$. This procedure is outlined and justified, along with the standard PMR method’s subtraction of counterterms mode-by-mode. We apply this method to calculate the renormalized energy-momentum fluxes ${⟨T_{uu}⟩}_{\mathrm{ren}}^U$, ${⟨T_{vv}⟩}_{\mathrm{ren}}^U$ (where $u$ and $v$ are the standard Eddington coordinates) and the renormalized field square ${⟨{\mathrm{\Phi }}^2⟩}_{\mathrm{ren}}^U$ throughout the Kerr black hole interior, spanning from (just off) the event horizon to (just off) the inner horizon. Special emphasis is placed on the vicinity of the inner horizon, where the $t$-splitting results for ${⟨T_{uu}⟩}_{\mathrm{ren}}^U$ and ${⟨T_{vv}⟩}_{\mathrm{ren}}^U$ asymptote to those obtained directly at the inner horizon using a different method in a previous work. In an Appendix, we develop an alternative variant of the $t$-splitting PMR method, dubbed the analytic extension variant, which does not include the intermediate divergence subtraction. We utilize it to perform independent computations that are used to verify the standard $t$-splitting variant presented in the main text.

We present a test of the equivalence principle on cosmological scales. This cornerstone of general relativity has been tested with high precision for standard matter, but its validity for the unknown dark matter remains a crucial open question. We construct a measurable quantity $E_P$ that acts as a null test, i.e. it deviates from unity whenever the weak equivalence principle is violated. This quantity can be directly measured from the cross-correlation of two different galaxy populations, thanks to the inclusion of large-scale relativistic corrections. A key feature of our approach is that it only involves minimal assumptions, without the need to specify the power spectrum shape, the background evolution, the growth rate of cosmic structure, the galaxy bias function or a model for the potential violation of the equivalence principle. We provide forecasts for the Dark Energy Spectroscopic Instrument and the Square Kilometre Array (SKA). While the relativistic corrections can be detected with high significance by both surveys, $E_P$ can be constrained up to an interesting level only by SKA, with a precision around 10%–15%.

A favored scenario for axions to be dark matter is for them to form a cosmic string network that subsequently decays, allowing for a tight link between the axion mass and relic abundance. We discuss an example in which the axion is protected from quantum gravity effects that would spoil its ability to solve the strong $CP$ problem: namely, a string theoretic axion arising from gauge symmetry in warped extra dimensions. Axion strings arise following the first-order Randall-Sundrum compactification phase transition forming at the junctions of three bubbles during percolation. Their tensions are at the low scale associated with the warp factor, and are parametrically smaller than the usual field-theory axion strings relative to the scale of their decay constant. Simulations of string network formation by this mechanism must be carried out to see whether the axion mass-relic density relation depends on the new parameters in the theory.

In the future, the third-generation gravitational wave (GW) detectors, exemplified by the Einstein Telescope (ET), will be operational. Many binary neutron star (BNS) coalescence events are expected to be observed. There are many machine learning works on binary black hole data analysis published, but works on BNSs are fewer. This paper explores the extraction of BNS waveforms from ET. Drawing inspiration from summed parallel infinite impulse response’s matched filtering approach, we introduce a novel framework based on leveraging deep learning for BNS waveform extraction. By integrating denoised outputs of time-delayed strain, we can reconstruct the embedded BNS waveform. We have established three distinct BNS GW denoising models, each tailored to address the early inspiral, later inspiral, and merger phases of BNS GWs, respectively. To further regulate the waveform shape, we propose an amplitude regularity model which takes the denoised output as input and output the regulated waveform. The experiments conducted on test data demonstrate the efficacy of the denoising models and the amplitude regularity model, as well as the overall waveform construction method. To the best of our knowledge, this marks the first instance of deep learning being utilized for the task of BNS waveform extraction. We also introduce a method for detecting BNS GWs that relies on waveform extraction. Our detection results demonstrate that this proposed method can accurately identify all GW signals with a SNR exceeding 20, without any false triggers. Furthermore, we believe that this GW extraction method also holds great promise for various other applications in BNS GW data processing, including localization and parameter estimation.