General Relativity and Quantum Cosmology
Cosmic voids are underdense regions that can provide an effective large-scale environment with a de Sitter-like gravitational behavior. Motivated by recent black-hole solutions embedded in void density profiles, we construct a symmetric…
We study the motion of spinning test particles in Schwarzschild spacetime within the Mathisson--Papapetrou--Dixon pole--dipole approximation, imposing the Tulczyjew--Dixon spin supplementary condition. Restricting to equatorial orbits with…
We investigate the modified thermodynamic properties of a deformed Schwarzschild black hole arising from new noncommutative corrections to the tetrad fields obtained through the Seiberg-Witten map. By deriving the corrected event horizon…
Spacetime torsion provides a natural extension of general relativity and may lead to black hole solutions that differ significantly from their Einsteinian counterparts. We investigate a class of Reissner-Nordstr\"om-like black holes in…
We investigate the thermodynamic and optical properties of Kerr--Bertotti--Robinson black holes, namely rotating black holes immersed in an external Bertotti--Robinson electromagnetic background. In the fixed-$a$ ensemble, we derive the…
We analyse the initial-value problem of metric higher-derivative effective theories of gravity. We show that any such theory whose characteristic velocities are independent of derivatives of the metric is intrinsically weakly hyperbolic,…
We study the thermodynamic properties and radiation characteristics of a regular compact object obtained by applying the Simpson-Visser regularisation to the Schwarzschild black hole in modified gravity. The resulting SV-MOG spacetime,…
We establish a universal connection between the classical energy conditions and directly observable black hole properties. By imposing the energy conditions locally at the photon sphere, we derive analytic and testable bounds on the shadow…
Analytic infinite derivative gravity theories provide a renormalizable and ghost-free description of gravity around covariantly constant backgrounds. These theories can have non-singular bouncing Universe solutions. In this paper we aim to…
Along with a whole range of alternative theories of gravity, variants of the massive theory of gravity, i.e. the theory of gravity, in which the graviton has mass, have been actively discussed in recent years. Theorists have proposed…
We solve the semiclassical Einstein equations for an evaporating Schwarzschild black hole in closed form, obtaining its backreacted geometry in 3+1 dimensions. This is achieved by a reformulation of the Hadamard renormalization…
This paper investigates a warm Dirac-Born-Infeld (DBI) inflationary model with nonminimal derivative coupling (NMDC) to gravity, where the inflaton kinetic term interacts with the Einstein tensor, thereby improving the effective…
We consider simple one dimensional models of acoustic black holes formed by Bose-Einstein condensates where the flow is stepwise homogeneous. We shall concentrate on the case in which an extended sonic region is present, i.e. a region where…
We numerically study perturbations of spatially homogeneous and orthogonal solutions to the Einstein-Euler equations with positive cosmological constant and linear equation of state $p=K\rho$ for $K \in (\frac{1}{3},1)$. Recent numerical…
We make use of the free data formalism developed in \cite{CK25,CK26} to provide a direct construction of short-pulse type Cauchy data. The construction of the spacelike short-pulse follows from the local existence result established in…
We study the propagation of high-frequency electromagnetic waves coupled to an axionic scalar field in curved spacetime. By applying the effective action approach, we go beyond the standard geometric optics limit and derive spinoptics…
Black holes are the sources of the strongest gravitational fields in the present-day Universe, offering unparalleled opportunities to test Einstein's theory of General Relativity in the strong-field regime. In this talk, I will examine the…
We investigate the thermodynamic modifications of the Reissner-Nordstroem anti-de Sitter (RN AdS) black hole induced by a minimal length scale,which naturally emerges in $\kappa$-deformed space-time. By constructing the modified metric via…
We derive the complete first post-Newtonian (1PN) Lagrangian and corresponding equations of motion for the relativistic $N$-body system in Scalar-Tensor-Fourth-Order Gravity (STFOG), including the Non-Commutative Spectral Geometry (NCSG)…
The threshold of black hole formation in axisymmetric vacuum gravity is proving to be more complicated than had been anticipated but, following recent advances, a consensus between independent codes and methods is emerging. Building on…