广义相对论与量子宇宙学

We develop a geometric realization of a broad class of generalized black hole entropy functionals by establishing their direct correspondence with the Misner$-$Sharp quasilocal mass and the Wald Noether$-$charge entropy in scalar$-$tensor…

Gravitational-wave observations provide a powerful probe of compact objects and strong-field gravity. In this work, we investigate the detectability of binaries containing (sub-)solar-mass black holes and superspinars with current and…

We study scalar field theories that break diffeomorphism invariance down to the subgroup of transverse diffeomorphisms through the matter sector in cosmological backgrounds. We focus on single- and multi-field models and develop the…

In this paper, we explore wormhole solutions in a higher-derivative theory of gravity where the action depends not only on the Ricci scalar \(R\), but also on its d'Alembertian, \(\Box R\). Such \(f(R,\Box R)\) models are motivated by…

By introducing a nonminimal coupling between the Kalb--Ramond field and the electromagnetic field, we construct an exact four-dimensional static, spherically symmetric dyonic black hole solution in Lorentz-violating gravity with a…

We investigate the quasinormal modes of a massless scalar field on an effective rotating loop quantum black hole background, constructed from a covariant spherical model via an improved Newman-Janis algorithm. Using the continued fraction…

Experimental constraints on the gravitational inverse-square law at short range are presented, employing a consistent formalism across a wide range of length scales. We provide comprehensive updates from the past decade, building upon our…

The study of shadows of static and rotating black holes immersed in various dark matter halo profiles has gained significant attention in recent years. In this paper, we consider the static black hole solution immersed in three dark matter…

A common approach in physics and mathematics is to extend and modify theories and frameworks by considering what is often described as a `natural' extension or modification by including higher-order terms or by introducing other…

We examine a proposed population of primordial, electrically charged compact objects, which we call astrons, with fiducial parameters \(M_A\sim10^{12}M_\odot\), \(Q_A\sim4\times10^{32}\,\mathrm{C}\), and megaparsec-scale separations. We…

Two primary formation channels for black holes have been proposed: the astrophysical channel, driven by the collapse of massive stars, and the primordial channel, involving their direct formation from density fluctuations in the early…

We investigate slow-roll inflation within the framework of Kaniadakis and dual Kaniadakis cosmology, where the usual entropy formalism is generalized through a deformation parameter $\kappa$. By deriving the modified Friedmann equations and…

We show that the emergence of time evolution in an otherwise timeless nonrelativistic closed quantum system -- viewed as a poor man's model of generally covariant quantum theory -- can be understood from the perspective of the path integral…

This work presents a new class of exact analytic rotating black hole solutions within five-dimensional generalized Proca theories. Through a Kerr-Schild ansatz where the Proca field is set along a null geodesic congruence, the non-linear…

We complete the visible, hidden, sectorial, and discrete symmetries of Ernst-like potential spaces in stationary, axisymmetric Einstein-Maxwell-Scalar Field (EMSF) and Einstein-ModMax-Scalar Field (EMMSF) theories. In the real potential…

In this work we address the possibility of having a positive running of the spectral index in inflationary theories. The recent ACT data indicate mildly that the running of the spectral index might be positive, and several other physical…

In this work, we investigate the scattering and absorption of spin 0 particles for electrically charged black holes in two gravity models with spontaneous Lorentz symmetry breaking. The first one is the so-called bumblebee model that…

We formulate the junction conditions for Scalar-Tensor-Vector Gravity (STVG/MOG), proposed by J.~W.~Moffat. Using these conditions, the theory of gravitational collapse is constructed. In the collapsing process, an interior…

Ultralight bosons with self-interactions, such as axion-like particles, can form astrophysical Bose-Einstein condensates around stars or compact objects, often referred to as gravitational atoms. In this work, we adopt a recently proposed…

In this work, we investigate the dynamic aspects of Bumblebee gravity via the parameterized post-Newtonian method. We find that the PPN framework is self-consistent up to 1.5PN order if and only if $\lambda = -\xi/2$, which corresponds to a…