Landau degeneracy and black hole entropy

TL;DR

This paper investigates the entropy of intersecting D-brane black holes, demonstrating a match between quantum D-brane counting and semi-classical calculations, emphasizing the role of Landau degeneracy in open-string states.

Contribution

It introduces a detailed analysis of D-brane entropy including Landau degeneracy effects, aligning quantum and semi-classical results for intersecting brane black holes.

Findings

Quantum D-brane entropy matches semi-classical calculations.

Landau degeneracy plays a crucial role in open-string state counting.

Near-extreme results are consistent with semi-classical predictions.

Abstract

We consider the supergravity solution describing a configuration of intersecting D-4-branes with non-vanishing worldvolume gauge fields. The entropy of such a black hole is calculated in terms of the D-branes quantised charges. The non-extreme solution is also considered and the corresponding thermodynamical quantities are calculated in terms of a D-brane/anti-D-brane system. To perform the quantum mechanical D-brane analysis we study open-strings with their ends on branes with a magnetic condensate. Applying the results to our D-brane system we managed to have a perfect agreement between the D-brane entropy counting and the corresponding semi-classical result. The Landau degeneracy of the open string states describing the excitations of the D-brane system enters in a crucial way. We also derive the near-extreme results which agree with the semi-classical calculations.