Black hole entropy as T-duality invariant

TL;DR

This paper investigates the invariance of D-brane entropies under T-duality, explores their relation to charges, and examines their microscopic interpretation, providing insights into black hole entropy in string theory.

Contribution

It demonstrates T-duality invariance of D-brane entropies and relates these entropies to microscopic states and charges, extending understanding of black hole entropy in string theory.

Findings

Entropies are T-duality invariant.

Finite entropies in the extremal limit are proportional to product of charges.

Entropies of boosted metrics relate to microscopic D-brane states.

Abstract

We study the Euler numbers and the entropies of the non-extremal intersecting D-branes in ten-dimensions. We use the surface gravity to constrain the compactification radii. We correctly obtain the integer valued Euler numbers for these radii. Moreover, the entropies are found to be invariant under the T-duality transformation. In the extremal limit, we obtain the finite entropies only for two intersecting D-branes. We observe that these entropies are proportional to the product of the charges of each D-brane. We further study the entropies of the boosted metrics. We find that their entropies can be interpreted in term of the microscopic states of D-branes.