Related papers: Acceleration of string loops in the Schwarzschild-…
Recently, Hawking radiation has been treated, by Robinson and Wilczek, as a compensating flux of the energy momentum tensor required to cancel gavitational anomaly at the event horizon(EH) of a Schwarzschild-type black hole. In this paper,…
We consider the effects of a cosmological constant on the dynamics of constant angular momentum discs orbiting Schwarzschild-de Sitter black holes. The motivation behind this study is to investigate whether the presence of a radial force…
In this work we consider a spacial kind of spacetime called AdS accelerating black holes. This is a kind of black holes which contain a stringlike singularity along polar axises attached to the black hole and it accelerates the black hole.…
The stability of Reissner-N\"ordstrom black holes with an extremal mass-charge relation was determined by calculating the propagation speed of gravitational waves on this background in an effective field theory (EFT) of gravity. New results…
We study stationary slowly rotating black holes, up to quadratic order in the spin angular momentum, in dynamical Chern-Simons gravity and shift symmetric Einstein scalar Gauss-Bonnet gravity, as models of string-inspired gravities. These…
Dyonic black holes with string-loop corrections are studied in the near-horizon region. In perturbative heterotic string theory compactified to four dimensions with N=2 supersymmetry, in the first order in string-loop expansion parameter,…
We study conserved charges and thermodynamics of analytic rotating anti-de Sitter black holes with extended horizon topology -- also known as black strings -- in dynamical Chern-Simons modified gravity. The solution is supported by a scalar…
We examine the effect of perturbative string loops on the cosmological pre-big-bang evolution. We study loop corrections derived from heterotic string theory compactified on a $Z_N$ orbifold and we consider the effect of the all-order loop…
A new method is applied for deriving the redshift and shadow of a Schwarzschild black hole moving freely in the de Sitter expanding universe as recorded by a co-moving remote observer. This method is manly algebraic focusing on the…
The capture of a straight, infinitely long cosmic string by a rotating black hole with rotation parameter $a$ is considered. We assume that a string is moving with velocity $v$ and that initially the string is parallel to the axis of…
We investigate the properties of a charged rotating black string immersed in a Kiselev anisotropic fluid in anti-de Sitter (AdS) spacetime. The Einstein-Maxwell equations with an anisotropic stress-energy tensor and cosmological constant…
In this study, we explore the dynamics of particle orbits and their corresponding gravitational wave signatures in the vicinity of a Schwarzschild black hole (BH) surrounded by a cloud of strings and embedded in a perfect fluid dark matter…
We investigate a static, spherically symmetric black hole solution surrounded by a cloud of strings and immersed in an electromagnetic universe. By deriving the event horizon from the lapse function, we demonstrate that both the string…
Utilising the master equation with source for perturbations of the Schwarzschild-Tangherlini solution, we construct perturbative solutions representing a black hole accelerated by a string in higher dimensions. We show that such solutions…
Effective field theories break down inside large black holes on macroscopic scales when tidal forces are string-sized. If $r_0$ is the horizon radius and $\alpha'$ is the square of the string scale, the 4D Schwarzschild interior is strongly…
String theory suggests the simultaneous presence of many ultralight axions possibly populating each decade of mass down to the Hubble scale 10^-33eV. Conversely the presence of such a plenitude of axions (an "axiverse") would be evidence…
Black holes are interesting astrophysical objects that have been studied as systems sensitive to quantum gravitational data. The accelerated geometry in the exterior of extremal black holes can induce large center-of-mass energies between…
Similar to the superradiant effect in Reissner-Nordstr\"{o}m black hole, a charged scalar field can be amplified when impinging on the charged black hole in string theory. According to the black-hole bomb mechanism,the mass term of the…
Stationary axisymmetric magnetic fields are expelled from outer horizons of black holes as they become extremal. Extreme black holes exhibit Meissner effect also within exact Einstein--Maxwell theory and in string theories in higher…
We investigate how GWs pass through the spacetime of a Schwarzschild black hole using time-domain numerical simulations. Our work is based on the perturbed 3+1 Einstein's equations up to the linear order. We show explicitly that our…