Instantons and seven-branes in type IIB superstring theory

TL;DR

This paper constructs and analyzes instanton and seven-brane solutions in type IIB supergravity, revealing their charge quantization, duality relations, and wormhole structure, with implications for charge conservation and non-perturbative effects.

Contribution

It provides explicit solutions for instantons and seven-branes in type IIB supergravity, detailing their charge properties, duality, and geometric structure, advancing understanding of non-perturbative phenomena.

Findings

Seven-branes carry quantized RR magnetic charge.

Instantons are non-singular in the string frame and have a wormhole geometry.

Charge product is constrained by Dirac quantization.

Abstract

Instanton and seven-brane solutions of type IIB supergravity carrying charges in the Ramond-Ramond sector are constructed. The singular seven-brane has a quantized \RR \ \lq magnetic' charge whereas its dual is the instanton, which is non-singular in the string frame and has an associated {\it global} \lq electric' charge. The product of these charges is constrained by a Dirac quantization condition. The instanton has the form of a space-time wormhole in the string frame, and is responsible for the non-conservation of the Noether current.