广义相对论与量子宇宙学

The Damour-Solodukhin wormhole (hereinafter DSWH) is known to mimic Schwarzschild black hole (hereinafter SBH) horizon in some properties. To act as a mimicker, the DSWH parameter $\lambda$ by definition is required to be extremely tiny,…

We present a covariant mechanism in which a smooth change of metric signature, from a Euclidean to a Lorentzian regime, drives a finite interval of accelerated expansion. The transition, encoded by a scalar interpolator along a timelike…

In this work, we examine the theoretical framework of modified teleparallel gravity with the inclusion of the boundary term in the action and investigate its cosmological implications by considering the power-law model $f(T, B) = -T +…

We extend our study of a cosmological scenario in which dark matter is non-minimally coupled to gravity at the fluid level. In previous work, we showed that this interaction can drive an early phase of accelerated expansion, addressing the…

We investigate the cosmological implications of the mass-to-horizon relation, which provides a unified framework for thermodynamically consistent generalized horizon-entropy functionals. Using the Cai-Kim formulation of the first law of…

We investigate the field of a point-like electric charge freely falling in a gravitational wave. In the presence of a gravitational wave, the initially static Coulomb field of the charge becomes time-dependent and generates corresponding…

We develop a geodesic-optics description of eikonal quasinormal ringing, blackhole shadows, strong lensing, grey-body factors (GBFs), and the binding energy of massive particles for the asymptotically flat regular black-hole geometry…

Globular clusters (GCs) can act as gravitational lenses for gravitational waves(GWs) in the wave-optics regime, imprinting frequency-dependent signatures on the observed signal. We investigate whether such lensing effects can be used to…

We consider a very general scale-invariant scalar-tensor theory of gravity and its flat cosmological solutions. We show that any stable configuration with non-degenerate gravitational dynamics carries a non-vanishing cosmological constant,…

Classically, black holes (BHs) are the most compact objects predicted in nature with C=0.5 in the Schwarzschild limit; C is defined as the mass-to-radius ratio in geometric units. In this work we perform a novel measurement on the nature of…

Several gravitational wave (GW) observations have been identified as binary black hole (BBH) mergers, including systems with component masses that challenge typical formation scenarios. These observations motivate broader tests of whether…

Gravitational waves are now routinely detected with ground-based observatories, and, through a process known as Bayesian inference, their source properties are inferred. However, terrestrial noise artifacts, often referred to as glitches,…

In this work, we investigate the distance duality relation (DDR) in symmetric teleparallel theories, where gravity is mediated by nonmetricity. Starting from the general metric-affine formulation and adopting the geometrical optics…

We study a broad class of constrained mimetic-type extensions of general relativity with action $S=\int{\rm d}^4x\sqrt{-g}\,\bigl(R/2+\lambda\,C[g,\Psi]+{\cal L}_{\rm m}\bigr)$, where $R$ is the Ricci scalar, $\lambda$ is a Lagrange…

We study the leading semiclassical backreaction of massive scalar, spinor, and vector fields in the spacetime of a pointlike global monopole. Starting from the renormalized stress-energy tensors obtained in the Schwinger--DeWitt…

We investigate the connection between cosmological stealth scalar fields and non-equilibrium thermodynamics in a spatially flat Friedmann-Lema\^{i}tre-Robertson-Walker (FLRW) background. We consider a non-minimally coupled scalar field…

We put forward a physical model of an accelerated Unruh-DeWitt battery moving along two distinct types of trajectories, namely a uniformly accelerated linear motion and a uniform circular motion. Each trajectory is considered without or…

We study here a novel application of Kim \& Lee charged wormholes assuming them to be dark halo objects playing the role of lenses in the Galactic microlensing with source stars belonging to the Galactic Bulge and the Large Magellanic…

Recently, a class of static spherically symmetric power law corrected Lorentz violating (LV) Schwarzschild black holes in the Kalb-Ramond model have been derived and studied in the specific range of LV parameters ($0<\lambda \leq 2,\Upsilon…

We prove small-data global stability of the Minkowski solution to Einstein's equations in a centre-normalised outgoing null-geodesic gauge. Our scheme involves first using the $r^p$-estimates of Dafermos-Rodnianski to control certain…