Massless radiation from heavy rotating string and Kerr/string correspondence

TL;DR

This paper calculates the emission spectrum of massless particles from highly excited rotating strings, demonstrating a thermal spectrum and exploring the correspondence between rotating strings and Kerr black holes.

Contribution

It derives the thermal emission spectrum, temperature, entropy, and angular velocity of rotating strings, and connects these findings to the Kerr/string correspondence principle.

Findings

Thermal spectrum observed in emission rates

Derived temperature and entropy of rotating strings

Established correspondence with Kerr black holes

Abstract

We calculate emission rates of a massless state from a highly excited rotating string in perturbative bosonic open string theory. By averaging huge degeneracies of initial string states with specifying the mass and a single component of the angular momentum, we find thermal spectrum in a wide range of the angular momentum. We derive the temperature that characterizes the thermal spectrum from the partition function of a single rotating string from which we also find the entropy and the angular velocity of rotating strings. We also argue based on these quantities the Horowitz-Polchinski correspondence principle between rotating strings/Kerr black holes for non-extremal as well as extremal cases. In the parameter region where the Kerr black holes exist, the thermal spectrum is comparable to scalar emissions from a rotating black hole.