Expanding F-Theory

TL;DR

This paper constructs new time-dependent solutions in non-linear sigma models coupled to gravity, describing expanding or contracting solitons with flexible tension constraints, applicable to string theory backgrounds with multiple 7-branes.

Contribution

It introduces a general class of solutions with flexible tension constraints, expanding the understanding of soliton configurations in gravity and string theory.

Findings

Solutions describe expanding/contracting codimension two solitons

Applicable to type IIB string theory with more than 24 7-branes

The transverse space is governed by the Liouville equation

Abstract

We construct a general class of new time dependent solutions of non-linear sigma models coupled to gravity. These solutions describe configurations of expanding or contracting codimension two solitons which are not subject to a constraint on the total tension. The two dimensional metric on the space transverse to the defects is determined by the Liouville equation. This space can be compact or non-compact, and of any topology. We show that this construction can be applied naturally in type IIB string theory to find backgrounds describing a number of 7-branes larger than 24.