General Relativity and Quantum Cosmology
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…
Motivated by the increasing efforts to understand the covariant structure of physical models associated with General Relativity using different kinds of geometric frameworks, in this article we analyze the four-dimensional Palatini-Cartan…
We introduce an explicit construction of the non-diagonal and diagonal Wigner distributions for the homogeneous but anisotropic Taub and Kantowski-Sachs cosmological models within the framework of phase space deformation quantization.…
We investigate the repetitive Penrose process for charged particles in an initially extremal Kerr--Newman black hole and develop a nonlinear iterative framework in which the black-hole mass, angular momentum, electric charge, and…
We investigate the geometrical, thermodynamic, and quantum emission properties of a rotating black hole immersed in a Hernquist dark matter halo. Starting from a static black hole spacetime surrounded by a Hernquist distribution, we…
We use numerical relativity to study the scalar field evolution sourced by hyperbolic encounters of black holes in quadratic scalar Gauss-Bonnet gravity. In this theory, single black holes are known to acquire a scalar hair through…
Bouncing cosmologies offer an alternative to the standard $\Lambda$CDM model by avoiding the problem of the initial cosmological singularity by construction. In these models, the universe undergoes a contraction phase that begins in a…
Modified black holes and black hole mimickers can give rise to additional photon rings in ray-traced images. With the photon ring structure of Kerr well understood, the question arises how well future versions of the Event Horizon Telescope…
The scalar-gauge pair formulation promotes gravitational coupling constants to conserved charges, clarifying their role in extended black hole thermodynamics. However, its original incarnation restricts these auxiliary scalar fields to…
Next-generation gravitational-wave detectors, such as LISA, the Einstein Telescope, and Cosmic Explorer, will require accurate and efficient models of long-lived black-hole binary signals, including those with significant eccentricity. A…
Pulsar timing arrays search for stochastic processes such as gravitational waves by comparing pulse time of arrival data for millisecond pulsars to expectations from a background with a given power spectral density (PSD). To make the…
Gibbons et al. [arXiv:hep-th/0408217] found the energy $E$ of Kerr--anti-de Sitter black holes by integrating the first law of black hole thermodynamics. They found that $E$ corresponds to the Ashtekar--Magnon--Das (AMD) energy associated…
In this comment we discuss some properties of the novel spacetime, recently found in [L. Ma, H. L\"{u}, arXiv:2606.23782]. In particular, we draw attention to the background of this solution that the authors claim to be a new spacetime. We…