arXiv subjects

Bhramar Chatterjee

Publications and source records attributed to Bhramar Chatterjee.

7 recordsLinked to original sources

arXiv2021

Black holes in Einstein-Gauss-Bonnet gravity: dynamical and 4-dimensional novel stationary black hole

We consider black hole in Einstein-Gauss-Bonnet(EGB) gravity in a dynamical setup and also the stationary black hole in recently discovered\cite{Glavan} $4$-dimensional novel Einstein-Gauss-Bonnet gravity. For dynamical EGB black hole in completely local settings we calculate the temperature associated with the horizon. For the stationary black hole in $4$-dimensional novel EGB theory we explore the thermodynamic properties including calculation of temperature and entropy.

gr-qc↗

arXiv2020

Estimation of temperature of cosmological apparent horizons: a new approach

We consider radiation from cosmological apparent horizon in Friedmann-Lemaitre-Robertson-Walker(FLRW) model in a double-null coordinate setting. As the spacetime is dynamic, there is no timelike Killing vector, instead we have Kodama vector which acts as dynamical time. We construct the positive frequency modes of the Kodama vector across the horizon. The conditional probability that a signal reaches the central observer when it is crossing from the outside gives the temperature associated with the horizon.

gr-qc↗

arXiv2012

Regularizing tunnelling calculations of Hawking temperature

Attempts to understand Hawking radiation as tunnelling across a black hole horizon require the consideration of singular integrals. Although Schwarzschild coordinates lead to the standard Hawking temperature, isotropic radial coordinates may appear to produce an incorrect value. It is demonstrated here how the proper regularization of singular integrals leads to the standard temperature for the isotropic radial coordinates as well as for other smooth transformations of the radial variable, which of course describe the same black hole.

gr-qc↗

arXiv2012

Hawking radiation from dynamical horizons

In completely local settings, we establish that a dynamically evolving black hole horizon can be assigned a Hawking temperature. Moreover, we calculate the Hawking flux and show that the radius of the horizon shrinks.

gr-qc↗

arXiv2012

Near-extremal black holes

We present a new formulation of deriving Hawking temperature for near-extremal black holes using distributions. In this paper the near-extremal Reissner-Nordstrom and Kerr black holes are discussed. It is shown that the extremal solution as a limit of non-extremal metric is well-defined. The pure extremal case is also discussed separately.

gr-qc↗

arXiv2009

Hawking temperature and higher order calculations

Hawking radiation has recently been explained by using solutions of wave equations across black hole horizons in a WKB approximation. Higher order calculations using both usual and non-singular coordinates are found to change the solution for zero spin, but this change is not an alteration of the Hawking temperature. For spin 1/2, there is no correction to the simplest form of the solution.

gr-qc↗

arXiv2008

Tunnelling from black holes and tunnelling into white holes

Hawking radiation is nowadays being understood as tunnelling through black hole horizons. Here, the extension of the Hamilton-Jacobi approach to tunnelling for non-rotating and rotating black holes in different non-singular coordinate systems not only confirms this quantum emission from black holes but also reveals the new phenomenon of absorption into white holes by quantum mechanical tunnelling. The role of a boundary condition of total absorption or emission is also clarified.

hep-th↗