Related papers: Amplification of waves from a rotating body
Rotating black holes are well known to amplify the perturbing bosonic fields in certain parameter spaces. This phenomenon is popularly known as superradiance. In addition to rotation in the spacetime, charge plays a crucial role in the…
A Regge--Wheeler analysis is performed for a novel black hole mimicker `the regular black hole with asymptotically Minkowski core', followed by an approximation of the permitted quasi-normal modes for propagating waveforms. A first-order…
This paper delineates the first steps in a systematic quantitative study of the spacetime fluctuations induced by quantum fields in an evaporating black hole. We explain how the stochastic gravity formalism can be a useful tool for that…
Using adiabatic point-particle black hole perturbation theory, we simulate plausible gravitational wave~(GW) signatures in two exotic scenarios (i) where a small black hole is emitted by a larger one ('black hole emission') and (ii) where a…
In turbulent flows subject to strong background rotation, the advective mechanisms of turbulence are superseded by the propagation of inertial waves, as the effects of rotation become dominant. While this mechanism has been identified…
There is abundant evidence that heating processes in the central regions of elliptical galaxies has both prevented large-scale cooling flows and assisted in the expulsion of metal rich gas. We now know that each such spheroidal system…
We use an optical centrifuge to deposit a controllable amount of rotational energy into dense molecular ensembles. Subsequent rotation-translation energy transfer, mediated by thermal collisions, results in the localized heating of the gas…
Accurate and powerful analytic and computational methods developped by the author allow to obtain the highly non trivial total absorption spectrum of the Black Hole, as well as phase shifts and cross sections (elastic and inelastic), the…
We derive some of the central equations governing quantum fluctuations in gravitational waves, making use of general relativity as a sensible effective quantum theory at large distances. We begin with a review of classical gravitational…
A classical black hole is characterized by a horizon that absorbs radiation of all frequencies incident on it. Perturbation of these black holes is well-understood via exponentially damped sinusoids known as quasi-normal modes. Any…
We study electromagnetic radiation reaction on a charged particle around a weakly magnetized Kerr black hole. We solve numerically the Teukolsky equation to find energy fluxes in electromagnetic radiation at the horizon and at spatial…
We study the classical and quantum black hole information in gravitational waves from a black hole's history. We review the necessary concepts regarding quantum information in many-body systems to motivate information retrieval and content…
Recently the possibility of detecting echoes of ringdown gravitational waves from binary black hole mergers was shown. The presence of echoes is expected if the black hole is surrounded by a mirror that reflects gravitational waves near the…
A distorted black hole radiates gravitational waves in order to settle down in a smoother geometry. During that relaxation phase, a characteristic damped ringing is generated. It can be theoretically constructed from both the black hole…
Accurate and powerful computational methods developed by the author for the wave scattering by black holes allow to obtain the highly non trivial total absorption spectrum of the Black Hole. As well as partial wave phase shifts and cross…
We present 3D numerical simulations and an analytic model of reflection-driven MHD turbulence in the solar wind. Our simulations describe transverse, non-compressive MHD fluctuations within a narrow magnetic flux tube that extends from the…
The prediction that black holes radiate due to quantum effects is often considered one of the most secure in quantum field theory in curved space-time. Yet this prediction rests on two dubious assumptions: that ordinary physics may be…
We introduce a mechanism that can both hold and amplify electromagnetic waves by rapidly changing the permittivity of the medium during the wave travel from a positive to a dispersionless (i.e. non-Foster) negative value and then back…
It has been shown that black hole quasinormal modes are subject to spectral instability, typically triggered by metric perturbations. These perturbations, which can introduce a minor bump in the effective potential of the wave equation,…
We consider the inward propagation of warping and eccentric disturbances in discs around black holes under a wide variety of conditions. In our calculations we use secular theories of warped and eccentric discs and assume the deformations…