Related papers: Scalar absorption: Black holes versus wormholes
We explore how to detect the large quantum fluctuations in the throat of a near-extremal black hole, where the dynamics are governed by the Schwarzian theory. To this end, we scatter a low-frequency wave of a massless, minimal scalar off…
In this work, we investigate the effects of Lorentz symmetry violation on the absorption cross section and quasinormal modes of a rotating acoustic black hole in (2+1) dimensions. The absorption cross section was analyzed analytically,…
It has long been known that null unstable geodesics are related to the characteristic modes of black holes-- the so called quasinormal resonances. The basic idea is to interpret the free oscillations of a black hole in the eikonal limit in…
We perform a comprehensive study of the emission of massive scalar fields by a higher-dimensional, simply rotating black hole both in the bulk and on the brane. We derive approximate, analytic results as well as exact numerical ones for the…
We classified and studied the charged black hole and wormhole solutions in the Einstein--Maxwell system in the presence of a massless, real scalar field. The possible existence of charged black holes in general scalar--tensor theories was…
It is known that, in the noncommutative Schwarzschild black hole spacetime, the point-like object is replaced by the smeared object, whose mass density is described by a Gaussian distribution of minimal width $\sqrt{\theta}$ with $\theta$…
An exact expression for the quasinormal modes of scalar perturbations on a massless topological black hole in four and higher dimensions is presented. The massive scalar field is nonminimally coupled to the curvature, and the horizon…
We study scalar and electromagnetic perturbations of a family of nonsingular nonrotating black hole spacetimes that are solutions in a large class of conformally invariant theories of gravity. The effective potential for scalar…
We study the evaporation of (4+n)-dimensional rotating black holes into scalar degrees of freedom on the brane. We calculate the corresponding absorption probabilities and cross-sections obtaining analytic solutions in the low-energy…
We study quasinormal modes, including the quasi-resonant regime, grey-body factors, and absorption cross sections of a massive scalar field in a Reissner--Nordstr\"om-like brane-world black hole endowed with a tidal-charge parameter induced…
The bell-like ringdown of the gravitational field in the last stage of the merging of massive black holes is now routinely detected on earth by the last generation of gravitational wave detectors. Its spectrum is interpreted as a sum of…
A model is proposed to describe a transition from a Schwarzschild black hole of mass $M_{0}$ to a Schwarzschild black hole of mass $M_{1}$ $\leq M_{0}$. The basic equations are derived from the non-vacuum Einstein field equations taking a…
We obtain the quasi-normal mode frequencies of scalar perturbation on new type black holes in three dimensional new massive gravity. In some special cases, the exact quasi-normal mode frequencies are obtained by solving scalar field…
We consider scattering and capture of circular cosmic strings by a Schwarzschild black hole. Although being a priori a very simple axially symmetric two-body problem, it shows all the features of chaotic scattering. In particular, it…
We analyze quasinormal modes, grey-body factors, and absorption cross-sections of a massive scalar field in the background of a Schwarzschild black hole surrounded by a Hernquist dark-matter halo. The quasinormal spectrum is obtained…
We study the quasinormal modes, Hawking radiation and absorption cross-section of the Bardeen black hole surrounded by perfect fluid dark matter for a massless scalar field. Our results show that the oscillation frequency of quasinormal…
We study the properties of the outgoing gravitational wave produced when a non-spinning black hole is excited by an ingoing gravitational wave. Simulations using a numerical code for solving Einstein's equations allow the study to be…
The massless conformally coupled scalar field is characterized by the so-called "new improved stress-energy tensor", which is capable of classically violating the null energy condition. When coupled to Einstein gravity we find a…
In this paper, we consider a massless field, with spin j, in interaction with a Schwarzschild black hole in four dimensions, focusing mainly our study on the s-wave scattering. First, using a Fourier analysis, we show that one can have a…
In 1921 Bach and Weyl derived the method of superposition to construct new axially symmetric vacuum solutions of General Relativity. In this paper we extend the Bach-Weyl approach to non-vacuum configurations with massless scalar fields.…