Related papers: Unexpectedly large surface gravities for acoustic …
Using the action principle we first review how linear density perturbations (sound waves) in an Eulerian fluid obey a relativistic equation: the d'Alembert equation. This analogy between propagation of sound and that of a massless scalar…
We propose a new analogue model of gravity - the evolving quark gluon plasma (QGP) produced in relativistic heavy ion collisions. This quark gluon plasma is the "most inviscid" fluid known. Such low kinematic viscosity is believed to…
Analogue black holes, which can mimic the kinetic aspects of real black holes, have been proposed for many years. The growth of the radial momentum of test particles toward the acoustic horizon is calculated for acoustic black holes in flat…
Acoustic black holes, analogs of gravitational black holes created in fluid systems, have recently been embedded within Schwarzschild spacetime using the Gross-Pitaevskii theory, leading to configurations with both event and acoustic…
Quantum fields in curved spacetime exhibit a wealth of effects like Hawking radiation from black holes. While quantum field theory in black holes can only be studied theoretically, it can be tested in controlled laboratory experiments. In…
We study the conditions under which an analog acoustic geometry of a relativistic fluid in flat spacetime can take the same form as the Schwarzschild black hole geometry. We find that the speed of sound must necessarily be equal to the…
For axially symmetric accretion maintained in hydrostatic equilibrium along the vertical direction, we investigate how the characteristic features of the embedded acoustic geometry depends on the background Kerr metric, and how such…
Black holes in general relativity are characterized by their trapping horizon, a one-way membrane that can be crossed only inwards. The existence of trapping horizons in astrophysical black holes can be tested observationally using a…
Four-dimensional, asymptotically flat spacetimes with an ergoregion but no horizon have been shown to be linearly unstable against a superradiant-triggered mechanism. This result has wide implications in the search for astrophysically…
We propose emulation of Hawking radiation (HR) by means of acoustic excitations propagating on top of persistent current in an atomic Bose-Einstein condensate (BEC) loaded in an annular confining potential. The setting is initially created…
A non-Riemannian geometrical approach to the investigation of an acoustic black hole in irrotational mean flows, based on the Lighthill vortex sound theory is given. This additional example of analog gravity based on classical fluids is…
The sound modes of a flowing superfluid is described by the massless Klein-Gordon equation in an effective background metric. This effective background metric can be designed to mimick a black hole using the acoustic horizon. In this work,…
We present the results of an analysis of superradiant energy flow due to scalar fields incident on an acoustic black hole. In addition to providing independent confirmation of the recent results in [5], we determine in detail the profile of…
Astrophysical black hole candidates, although long thought to have a horizon, could be horizonless ultra-compact objects. This intriguing possibility is motivated by the black hole information paradox and a plausible fundamental connection…
This thesis explores two avenues into understanding the physics of black holes and horizons beyond general relativity, via analogue models and Lorentz violating theories. Analogue spacetimes have wildly different dynamics to general…
Acoustic waves in fluids undergoing the transition from sub- to supersonic flow satisfy governing equations similar to those for light waves in the immediate vicinity of a black hole event horizon. This acoustic analogy has been used by…
We consider an irrotational plasma fluid evolving under the effect of a background magnetic field. The magnetohydrodynamic formalism is used to describe the electromagnetic waves and the dynamics is described by a scalar field that follows…
We formulate and solve the equations governing the transonic behaviour of a general relativistic black-hole accretion disc with non-zero advection velocity. We demonstrate that a relativistic Rankine-Hugoniot shock may form leading to the…
Among all the different techniques to derive the Hawking effect, the approach based on gravitational anomaly by Robinson and Wilczek provides a simple and satisfactory origin of the black hole radiation. In this picture, the effective near…
We study the robustness of the spectrum emitted by an acoustic black hole by considering series of stationary flows that become either subsonic or supersonic, i.e. when the horizon disappears. We work with the superluminal Bogoliubov…