CAAUL Seminar - Black hole entropy through thin matter - 11 novembro 2013

Black hole entropy through thin matter

Gonçalo Quinta

IST

Abstract / Resumo

We study the thermodynamics of thin matter shells in the context of general relativity, as well as the implications of such study for the entropy of black holes. We follow the same work methodology in a variety of cases, which starts by using Israel’s formalism to obtain the necessary pressure and energy of the thin shell in order for it to be static. Those quantities are then used to find the entropy of the shell which naturally possesses degrees of freedom that can be parametrized by phenomenological functions which contain free parameters. These last are then subject to an analysis which determines the interval of values for which the thermodynamic stability of the system is guaranteed. This process is repeated for 4 different situations: a shell in 2+1 dimensions; a shell in 2+1 dimensions with a non-null cosmological constant; a shell in d dimensions; and an electrically charged shell in 4 dimensions. Lastly, we use the results obtained for the shells in the limit where they are taken to their gravitational radius, where it is shown that they can behave like black holes.

In particular, the case of a charged shell in the extremal limit suggests a solution for the ongoing debate concerning the value of the entropy of an extremal black hole.

11 de novembro de 2013 | 11:00

Local

Faculdade de Ciências da Universidade de Lisboa

Edifício C8 | Sala 1.67