Counting States of Black Strings with Traveling Waves

TL;DR

This paper constructs and analyzes six-dimensional extremal black string solutions with traveling waves, demonstrating that their entropy matches the count of BPS states at weak coupling, linking microscopic states to macroscopic geometry.

Contribution

It introduces a family of inhomogeneous black string solutions with traveling waves and shows their entropy matches BPS state counts, connecting microscopic and macroscopic descriptions.

Findings

Horizon area computed for solutions with traveling waves

Number of BPS states matches Bekenstein-Hawking entropy

Solutions depend on arbitrary functions, indicating rich structure

Abstract

We consider a family of solutions to string theory which depend on arbitrary functions and contain regular event horizons. They describe six dimensional extremal black strings with traveling waves and have an inhomogeneous distribution of momentum along the string. The structure of these solutions near the horizon is studied and the horizon area computed. We also count the number of BPS string states at weak coupling whose macroscopic momentum distribution agrees with that of the black string. It is shown that the number of such states is given by the Bekenstein-Hawking entropy of the black string with traveling waves.