Power-law corrections to black-hole entropy via entanglement

Abstract

We consider the entanglement between quantum field degrees of freedom inside and outside the horizon as a plausible source of black-hole entropy. We examine possible deviations of black hole entropy from area proportionality. We show that while the area law holds when the field is in its ground state, a correction term proportional to a fractional power of area results when the field is in a superposition of ground and excited states. We compare our results with the other approaches in the literature.Comment: 10 pages, 5 figures, to appear in the Proceedings of "BH2, Dynamics and Thermodynamics of Blackholes and Naked Singularities", May 10-12 2007, Milano, Italy; conference website: http://www.mate.polimi.it/bh2