Instanton Moduli and Brane Creation

TL;DR

This paper constructs new intersecting brane solutions in heterotic string theory supported by Yang-Mills instantons, revealing phase transitions that affect black hole entropy and demonstrate instanton-induced brane creation.

Contribution

It introduces novel intersecting brane solutions supported by instantons and uncovers phase transitions leading to brane and string creation, impacting black hole entropy calculations.

Findings

Phase transitions occur when instanton size vanishes or instantons coalesce.

Black hole entropy is zero with separated, finite-size instantons.

Entropy becomes non-zero after phase transitions, enabling microscopic counting.

Abstract

We obtain new intersecting 5-brane, string and pp-wave solutions in the heterotic string on a torus and on a K3 manifold. In the former case the 5-brane is supported by Yang-Mills instantons, and in the latter case both the 5-brane and the string are supported by the instantons. The instanton moduli are parameterised by the sizes and locations of the instantons. We exhibit two kinds of phase transition in which, for suitable choices of the instanton moduli, a 5-brane and/or a string can be created. One kind of phase transition occurs when the size of an instanton vanishes, while the other occurs when a pair of Yang-Mills instantons coalesce. We also study the associated five-dimensional black holes and the implications of these phase transitions for the black-hole entropy. Specifically, we find that the entropy of the three-charge black holes is zero when the instantons are separated and of non-zero scale size, but becomes non-zero (which can be counted miscrospically) after either of the phase transitions.