Research Projects

We are in the midst of a revolutionary era in gravitational physics, which will shape the future of both theoretical gravitational physics, as well as that of astronomy and astrophysics. The not-so-recent detection of gravitational waves (GWs) from the merger of a binary black hole system and neutron stars has provided an unprecedented view of the dynamics of gravity in the near horizon regime. Since, these scenarios involve binaries of compact objects coalescing at close to the speed of light, they are capable of providing information about the nature of gravity in the extreme regimes, which was hitherto unavailable. This new tool has the ability to provide us, with precession, the nature of gravitational interaction in the strong-field regime, of which we have had no experimental verifications before. Thus with the detections of more and more coalescing compact binaries and also observing shadow of various other compact objects will enable us to unravel possible new physics beyond general relativity (GR) and also to study the BH nature of compact objects. As the GW astronomy comes to its youth, the possibility of exploring the quantum nature of BHs becomes a real possibility. In particular, the GWs emitted from the merging BH binaries can indeed carry information about the quantum nature of the BHs. The fact that a thought-to-be classical GW observation can actually extract quantum information about its sources is a fascinating possibility and will form one of the main thrust of this project. Quantum BHs are expected to have a discrete energy spectrum, which is what we expect from any quantum system and hence in this respect these behave as excited atoms. There are various different ways in which quantum properties can be embedded to a BH --- (a) through some theory of quantum gravity, e.g., Loop Quantum Gravity and String Theory; (b) replacing the BH with a membrane consisting of quantum fluid; (c) based on the results that the BH area (A) behaves as an adiabatic invariant, one can invoke the ``Bohr-Sommerfeld"-like quantization of the area spectrum. All of these approaches towards ``quantizing" a BH keep their imprints on the GWs emitted from these and hence is worth looking for in the GW signals received by the LIGO, the VIRGO and in future also by the LIGO-India observatory. The present study will aim to answer these questions --- which are with us for the last four decades --- regarding the nature of (quantum) gravity in the strong field regime, existence of BHs in our universe and most importantly resolving the puzzles involving BH singularity. Besides, we wish to identify several key observables, which holds the information regarding the nature of gravity and of the black holes. So that comparing the theoretical estimations of these observables with the GW data, one can make important statements about the black hole nature of compact objects and also about gravity theories beyond general relativity.

Gravitational Waves, Black Hole Physics, Modified Gravity,