Physics

Dr. Swastik Bhattacharya
IISER, Trivandrum

It is well-known that the Black Hole horizon obeys the equation of
motion for a viscous fluid. A statistical model of this fluid can help
us obtain some insight into the thorny problems of the microscopic
Black Hole degrees of freedom and Black Hole entropy. In this talk, we
shall take this fluid to be of a physical origin and construct a
Theory of Fluctuations for it. In particular, I shall show that the
Langevin equation governing the energy transported from outside into
the horizon-fluid corresponds to the Raychaudhuri equation for the
null congruences on the Black Hole horizon. We shall also briefly
outline a method, that uses the Kubo formula to compute the
coefficient of Bulk Viscosity of the Horizon fluid. We shall show that
this comes out to be negative due to the teleological nature of the
Black Hole event horizon..Finally, I shall briefly outline how it is
possible to have a statistical mechanical understanding of the
negative specific heat of Black Holes in a similar manner.