1212.6877 (Hristu Culetu)

Comment on "Empty Black Holes, Firewalls, and the Origin of
Bekenstein-Hawking Entropy"    [PDF]

Hristu Culetu

Saravani, Afshordi and Mann \cite{SAM} considered a surface fluid with vanishing energy density on the stretched horizon of a black hole, taken as the new boundary of spacetime. We show that their entropy per unit area of the fluid does not correspond to the Bekenstein-Hawking entropy, both for a Schwarzschild black hole and for a Kerr-Newman black hole. Due to the lack of a horizon, we argue that the Unruh effect could not be taken into account and the concept of local thermodynamic equilibrium is not sustained because of the $\theta$-dependence of the temperature.

View original: http://arxiv.org/abs/1212.6877