We demonstrate that short-period stars orbiting around the supermassive black hole in our
Galactic center can successfully be used to probe the gravitational theory in a strong regime …

We investigate the gravitational lensing effect around a spherically symmetric black hole,
whose metric is obtained from the Einstein field equation with electric charge and perfect …

In this paper, we investigate the gravitational lensing effect and the shadow around a
Schwarzschild-like black hole in metric-affine bumblebee gravity, which leads to the Lorentz …

Gravitational lensing is one of the most impressive celestial phenomena, which has
interesting behaviors in its strong field limit. Near such limit, Bozza finds that the deflection …

The effects of a nonminimally coupled curvature-matter model of gravity on a perturbed
Minkowski metric are presented. The action functional of the model involves two functions f 1 …

We study light rays in the static and spherically symmetric gravitational field of the null aether
theory (NAT). To this end, we employ the Gauss-Bonnet theorem to compute the deflection …

In this paper, the homotopy-perturbation method (HPM) is applied to obtain approximate
analytical solutions for the gravitational deflection of light in General Relativity near …

We propose a new approach in studying the planetary orbits and the perihelion precession
in General Relativity by means of the Homotopy Perturbation Method (HPM). For this …

This work studies the periapsis shift in the equatorial plane of arbitrary stationary and
axisymmetric spacetimes. Two perturbative methods are systematically developed. The first …

We present a quantum field theoretical derivation of the nondecay probability of an unstable
particle with nonzero three‐momentum p. To this end, we use the (fully resummed) …