The library of Babel: on the origin of gravitational thermodynamics
Abstract
We show that heavy pure states of gravity can appear to be mixed states to almost all probes. For AdS_{5} Schwarzschild black holes, our arguments are made using the field theory dual to string theory in such spacetimes. Our results follow from applying information theoretic notions to field theory operators capable of describing very heavy states in gravity. For halfBPS states of the theory which are incipient black holes, our account is exact: typical microstates are described in gravity by a spacetime ``foam'', the precise details of which are almost invisible to almost all probes. We show that universal lowenergy effective description of a foam of given global charges is via certain singular spacetime geometries. When one of the specified charges is the number of Dbranes, the effective singular geometry is the halfBPS ``superstar''. We propose this as the general mechanism by which the effective thermodynamic character of gravity emerges.
 Publication:

Journal of High Energy Physics
 Pub Date:
 December 2005
 DOI:
 10.1088/11266708/2005/12/006
 arXiv:
 arXiv:hepth/0508023
 Bibcode:
 2005JHEP...12..006B
 Keywords:

 High Energy Physics  Theory
 EPrint:
 LaTeX, 6 eps figures, uses young.sty and wick.sty