A String Model of Black Hole Microstates

The statistical mechanics of black holes arbitrarily far from extremality is modeled by a gas of weakly interacting strings. As an effective low energy description of black holes the model provides a number of highly non-trivial consistency checks and predictions. Speculations on a fundamental origin of the model suggest surprising simplifications in non-perturbative string theory, even in the absence of supersymmetry. Black holes exhibit thermodynamic properties suggestive of a complicated internal structure. This is somewhat paradoxical within standard general relativity where black holes are absolutely featureless. In the last year or so there has been considerable excitement as it has become clear that string theory can accurately account for the degeneracy implicit in the BekensteinHawking entropy. This development initially concerned the counting of states for extremal [1, 2, 3] and near extremal black holes [4, 5]. The effective string model that emerged apparently describes in much detail the dynamics of near extremal black holes [6, 7, 8, 9]. This no longer leaves any doubt that string theory describes many features of black holes. Many questions remain however. Current models are restricted to very large wave lengths. In the interesting region with possible information loss the appropriate methods are quite different and they still need further development [10, 11, 12, 13]. The focus of this Letter is another ill-understood e-mail: [email protected]