23 papers
Electrically Charged Distorted Black Holes: Thermodynamics, Particle Dynamics, and Quasinormal Signatures
Gamal G. L. Nashed, Salvatore Capozziello
We construct an exact solution for the electrically charged extension of a distorted black hole spacetime within Einstein-Maxwell theory using the Harrison transformation. The resu…
Primordial Black Hole Formation in Gravity: Perturbative and Non-Perturbative Analysis
G. G. L. Nashed, A. Eid
We present a complete analytic and semi-analytic study of gravitational collapse and primordial black hole (PBH) formation in the quadratic model . We first de…
Late-Time Cosmology and Structure Formation in Quadratic Gravity
G. G. L. Nashed, P. V. Tretyakov, A. Eid
We investigate the cosmological evolution associated with the quadratic symmetric teleparallel gravity framework, \( f(Q)=Q+αQ^{2}+β\) where the relation \(Q\propto H^{2}\) gener…
3-dimensional charged black holes in gravity
G. G. L. Nashed, Emmanuel N. Saridakis
We present new exact charged black hole solutions in (2+1) dimensions within the framework of gravity, where denotes the non-metricity scalar. By considering a cubic…
Analytic semiclassical backreaction of a Schwarzschild black hole in a finite cavity: horizon shift, temperature renormalization, and canonical stability in the Hartle-Hawking State
G. G. L. Nashed, Alnadhief H. A. Alfedeel, Tiberiu Harko
We construct an analytic model of static semiclassical backreaction for a Schwarzschild black hole in the Hartle--Hawking state enclosed within a finite spherical cavity. Using a m…
A Minimal and Stable Vacuum Bounce in Exponential Gravity
G. G. L. Nashed, A. Eid
We investigate the realization of a nonsingular cosmological bounce in metric gravity using a controlled exponential deformation of the Starobinsky model. Adopting a…