Strings and black holes

TL;DR

This paper reviews work demonstrating a correspondence between self-gravitating string states and Schwarzschild black holes, showing how increasing string coupling causes strings to shrink into black hole-like states with matching properties.

Contribution

It provides a detailed calculation confirming the transition from string states to black holes and supports the idea that black hole entropy can be explained by string state counting.

Findings

String states shrink and become black hole-like as coupling increases.

Black hole entropy can be accounted for by string state counting.

Quantum level spacing of black holes is exponentially small and blurred.

Abstract

I review some recent work (done in collaboration with G. Veneziano) which clarifies the existence of a correspondence between self-gravitating fundamental string states and Schwarzschild black holes. The main result is a detailed calculation showing that self-gravity causes a typical string state of mass M to shrink, as the string coupling g^2 increases, down to a compact string state whose mass, size, entropy and luminosity match (for the critical value g_c^2 = (M sqrt{alpha'})^{-1}) those of a Schwarzschild black hole. This confirms the idea that the entropy of black holes can be accounted for by counting string states, and suggests that the level spacing of the quantum states of Schwarzschild black holes is exponentially small, and very much blurred by radiative effects.