BPS Spectrum of the Five-Brane and Black Hole Entropy

TL;DR

This paper develops a new formulation of M-theory using five-branes with closed strings, enabling the calculation of BPS spectra and black hole entropy in various dimensions, consistent with U-duality.

Contribution

It introduces a novel five-brane based formulation of M-theory to compute BPS spectra and black hole entropy, aligning with U-duality in six dimensions.

Findings

BPS spectrum matches U-duality predictions

Degeneracy calculations agree with black hole entropy

Framework applies to compactifications in 6 and 5 dimensions

Abstract

We propose a formulation of 11-dimensional M-theory in terms of five-branes with closed strings on their world-volume. We use this description to construct the complete spectrum of BPS states in compactifications to six and five dimensions. We compute the degeneracy for fixed charge and find it to be in accordance with U-duality (which in our formulation is manifest in six dimensions) and the statistical entropy formula of the corresponding black hole. We also briefly comment on the four-dimensional case.