Moving Five-Branes in Low-Energy Heterotic M-Theory

TL;DR

This paper constructs cosmological solutions in heterotic M-theory featuring a moving five-brane, revealing how brane motion influences the evolution towards strong coupling and transitions between different solution regimes.

Contribution

It introduces explicit four-dimensional solutions with dynamic five-branes and analyzes their impact on the evolution of heterotic M-theory cosmologies.

Findings

Five-brane induces transition between asymptotic solutions

Solutions tend toward strong coupling over time

Explicit example of brane collision with small-instanton transition

Abstract

We construct cosmological solutions of four-dimensional effective heterotic M-theory with a moving five-brane and evolving dilaton and T modulus. It is shown that the five-brane generates a transition between two asymptotic rolling-radii solutions. Moreover, the five-brane motion always drives the solutions towards strong coupling asymptotically. We present an explicit example of a negative-time branch solution which ends in a brane collision accompanied by a small-instanton transition. The five-dimensional origin of some of our solutions is also discussed.