arXiv subjects

Saneesh Sebastian

Publications and source records attributed to Saneesh Sebastian.

5 recordsLinked to original sources

arXiv2014

Scalar and Electromagnetic Quasinormal modes of Extended black hole in F(R) gravity

In this paper we study the scalar and electromagnetic perturbations of an extended black hole in F(R) gravity. The quasinormal modes in two cases are evaluated and studied their behavior by plotting graphs in each case. To study the quasinormal mode, we use the third order WKB method. The present study shows that the absolute value of imaginary part of complex quasinormal modes increases in both cases, thus the black hole is stable against these perturbations. As the mass of the scalar field increases the imaginary part of the frequency decreases. Thus damping slows down with increasing mass of the scalar field.

gr-qc↗

arXiv2014

Scattering of Scalar Field by an Extended Black Hole in F(R) gravity

In this work we have studied the scattering of scalar field around an extended black hole in F(R) gravity using WKB method. We have obtained the wave function in different regions such as near the horizon region, away from horizon and far away from horizon and the absorption cross section are calculated. We find that the absorption cross section is inversely proportional to the cube of Hawking temperature. We have also evaluated the Hawking temperature of the black hole via tunneling method.

gr-qc↗

arXiv2014

Dirac Quasinormal modes of MSW black holes

In this paper we study the Dirac quasinormal modes of an uncharged 2 + 1 black hole proposed by Mandal et. al and referred to as MSW black hole in this work. The quasi- normal mode is studied using WKB approximation method. The study shows that the imaginary part of quasinormal frequencies increases indicating that the oscillations are damping and hence the black hole is stable against Dirac perturbations.

gr-qc↗

arXiv2013

Spectroscopy and Thermodynamics of MSW Black Hole

We study the thermodynamics and spectroscopy of a 2+1 dimensional black hole pro- posed by Mandal et. al1 . We put the background space time in Kruskal like co-ordinate and find period with respect to Euclidean time. Different thermodynamic quantities like entropy, specific heat, temperature etc are obtained. The adiabatic invariant for the black hole is found out and quantized using Bohr-Sommerfeld quantization rule. The study shows that the area spectrum of MSW black hole is equally spaced and the value of spacing is found to be h bar

gr-qc↗

arXiv2011

A Mond Programme from Einstein Hilbert Action

In the usual derivation of Einstein's equation from action, the surface terms are neglected. Hawking \cite{hw} gave a derivation of the gravitational Hamiltonian keeping all surface terms. Using such surface terms Easson et.al.\cite{ea} showed that Friedmann equation could get modified and using the modified Friedmann equation they could explain the cosmic acceleration. We study the effect of surface terms on a galactic scale and find that the classical limit of the modified Friedmann equation will lead to a MOND like acceleration term.

gr-qc↗