广义相对论与量子宇宙学
A small fraction of the gravitational waves (GWs) currently observable by LIGO, Virgo, and KAGRA (LVK) may be strongly lensed by intervening galaxies and galaxy clusters, potentially producing multiple copies of the same signal. We search…
The Laser Interferometer Space Antenna (LISA) will search for a stochastic gravitational-wave (GW) background at millihertz frequencies, from both astrophysical and cosmological sources, and thereby open a new chapter in GW astronomy. In…
A covariant reconstruction framework for Kantowski--Sachs (KS) geometries sourced by Chaplygin-type and polytropic fluids in teleparallel $F(T)$ gravity is developed using the coframe--spin-connection formalism and the invariant…
We study linear gravito-electromagnetic perturbations of a slowly rotating 4-derivative corrected Kerr-Newman (KN) black hole (BH), using a perturbative approach beyond the KN geometry up to first order in angular momentum, first order in…
We study the five-dimensional Schwarzschild-Tangherlini solution, with particular attention to its geodesic structure and massless scalar perturbations. In the probe limit, we present two applications. First, we compute the scattering angle…
A massive fermion around a charged black hole provides a gravitational analogue of atomic bound states and their relaxation. In this work, we study this system by formulating the radial equation as a coupled matrix system and constructing…
Regular black holes in Horndeski theories must have stable horizons and regular centers. We study static, spherically symmetric, asymptotically flat configurations with a time-independent scalar. The horizon branch on which the scalar…
We investigate non-Hermitian $\mathcal{PT}$-symmetric Klein--Gordon (KG) fields in a magnetized cosmic string spacetime. A complex non-minimal scalar interaction, $\mathcal{F}_{\mu}=(0,\mathcal{F}_{r},0,0)$ with $\mathcal{F}_{r}=\omega…
One of the technical anchors of JVN's research was the "action-at-a-distance" view of gravitational interaction, driven by "Mach's Principle" addressing the origin of inertia. This view exorcises the concept of a field as a mediator of…
We present an exact analytical model describing a complete gravitational collapse of matter from horizonless initial conditions to black hole formation, tracing the full evolution of the horizon $H(t)$ from its formation at microscopic…
We present a new class of exact solutions in Einstein-Gauss-Bonnet gravity in 2+1 dimensions that generalize the C-metric. This set of metrics equals the C-metric multiplied by a factor which, along with the massless scalar field, depends…
We present a novel rotating black hole solution surrounded by a Hernquist dark matter halo, obtained by applying the Newman--Janis algorithm to the exact Schwarzschild--Hernquist spacetime. The resulting Kerr--Hernquist geometry provides an…
Recently it was shown that a non-local T-duality-inspired smearing of the point mass introduces a finite zero-point length, while the regularized Newtonian gravitational self-energy is promoted to an additional source for the spacetime. The…
We study tides during the inspiral of a binary neutron star (BNS) system, including nonlinear hydrodynamical interactions. Using an affine approximation that treats the perturbed NS as an ellipsoid, we analytically derive coupling…
We introduce a static, horizonless, asymptotically flat two throat wormhole family in which one global metric determines the geometry, effective source, null dynamics, lensing, and test field propagation. A finite mass deformation of a…
We present a general construction of charged regular black holes as solutions of a generalization of the Einstein--Maxwell field equations in spherical symmetry in which the Einstein tensor is deformed into an identically conserved tensor…
We show that cosmological models with a semi-infinite phase of slow contraction (ekpyrosis) possess a combination of properties that can address several fundamental problems in cosmology, otherwise faced in contracting de Sitter phases or…
We study a one-loop corrected extension of the classical Callan-Giddings-Harvey-Strominger (CGHS) model of two-dimensional dilaton gravity. The effective action combines the non-local Polyakov action for matter fluctuations, a Polyakov-type…
We present infinite-derivative completions of Quasitopological gravities that are ghost-free, avoid strong coupling instabilities and admit exact, spherically symmetric vacuum regular-black-hole solutions satisfying a perturbative Birkhoff…
The Event Horizon Telescope (EHT) has provided images of the supermassive black-holes Sgr A$^{*}$ and M87$^{*}$, enabling direct tests of gravity. Any extended mass-distribution, such as a dark-matter halo, perturbs null-geodesics in the…