General Relativity and Quantum Cosmology
Within the framework of generalised entropic cosmology and its equivalent $f(Q)$ gravity, we construct inflationary scenarios consistent with recent Atacama Cosmology Telescope (ACT) observations combined with Planck-BAO data. We work with…
We investigate a class of time-dependent traversable wormholes within the framework of general relativity by allowing the shape function to vary with time. In this setting, the evolution of the geometry is directly connected to a radial…
We propose an effective, singularity-free model of the black hole interior described entirely by a scalar field with a non-linear self-interaction potential. The interior consists of three layers -- a core, a transition layer, and a crust…
In eternal black-hole spacetimes, inner horizons are Cauchy horizons and are generically unstable. For non-extremal inner horizons, this includes both the classical mass-inflation instability and a semiclassical instability associated with…
Gravitational lensing of gravitational waves can probe compact lenses, dark matter substructure, and cosmological distances, but identifying lensed events is difficult when unrelated binary mergers overlap in the same analysis window. We…
The frequency-domain gravitational waveform emitted by the scattering of two non-spinning massive particles has recently been derived at next-to-leading, \textit{i.e.} one-loop, post-Minkowskian order, $h(\omega, \theta,\phi) \sim G^2 +…
To probe the interplay between dark matter (DM) and non-linear electrodynamics (NED), we consider the Bardeen black hole (BH) surrounded by perfect fluid dark matter (PFDM). We first compute the effective potential governing the particle…
In this paper, we study the optical appearance of a 4D Einstein-Gauss-Bonnet asymmetric thin-shell wormhole. Using Visser's cut-and-paste construction, we determine the photon sphere radius and critical impact parameter for different values…
We study axial gravitational perturbations of the neutral regular black hole generated by a non-local, T-duality-inspired zero-point length and the associated gravitational self-energy. In this geometry, the usual point source is replaced…
We unify two independent notions of effective temperature in dynamical thin-shell wormholes: the local acceleration temperature of the throat and the Hawking-like particle-creation temperature governed by the peeling of null rays. The…
Swift memory burden (MB) implies that the information stored in a black hole (BH) can modify its classical dynamics when the BH is perturbed. This influences the gravitational waves (GWs) emitted during BH mergers. In this paper, we…
This work explores the reconstruction of $f(R)$ gravity within the framework of newly proposed Viaggiu holographic dark energy (VHDE), which incorporates entropy corrections due to the dynamical nature of cosmological horizons. By…
In various approaches to quantum gravity, spacetime geometry is understood to emerge from more fundamental discrete structures at the Planck scale. As sometimes posited, their presence could lead to dissipative effects in the smooth…
The ringdown waves from a black hole offer a clean probe of strong-field gravity, but a matter distribution that may be present around a realistic black hole renders the background spacetime dynamical and the ringdown frequencies…
Let $\{\Sigma_t\}$ be a spacelike foliation of a spacetime $\mathcal{M}$, and suppose each $\Sigma_t$ is foliated by 2-surfaces $\mathcal{S}$ with spacelike unit normal in $\Sigma_t$. We show that under mild energy conditions, a MOTS…
We study static, spherically symmetric solutions in $f(R)$ gravity within a $D = 4+n$-dimensional spacetime, where the extra dimensions form a compact $n$-sphere of constant radius. We derive an exact solution in which the four-dimensional…
Primordial black holes (PBHs) form when large primordial curvature perturbations re-enter the Hubble radius and exceed the classical collapse threshold. These perturbations originate as quantum fluctuations of the inflationary vacuum,…
In this work, we investigate the gravitational lensing properties of a static Ellis-Bronnikov wormhole embedded in a curved Friedmann-Lema\^itre-Robertson-Walker (FLRW) universe. By employing curvature-dependent cosmological distances, we…
In this paper, an interactive Holographic Dark Energy (HDE) model is studied in the framework of modified gravity \(f(Q)\). By adopting a power parameterization for the Hubble parameter, the field equations are reconstructed and the…
We explore the Kazakov-Solodukhin quantum-deformed black hole spacetime, characterized by a single deformation parameter \( \eta \) that encodes quantum corrections to the classical Schwarzschild solution. The model preserves the correct…