Exact Four Dimensional Exploding Universe Solution in String Theory

TL;DR

This paper presents an exact four-dimensional universe solution in string theory that exhibits explosive expansion, derived via non-abelian T-duality and analytic continuation, featuring a finite radius universe with a boundary moving at light speed.

Contribution

It introduces a novel exact solution in string theory describing an exploding universe with a boundary, expanding the understanding of cosmological models within string theory.

Findings

The universe's radius remains finite at fixed times.

The boundary of the universe moves at the speed of light.

Flat space-time is recovered after the boundary moves away.

Abstract

We obtain a four dimensional exploding universe solution in string theory. The solution is obtained from the string theory in the flat background by using non-abelian $T$-duality and the analytic continuation. In the solution, the radius of the universe is finite for fixed time and the universe is surrounded with the boundary which is composed of the singularity. The boundary runs away with the speed of light and the flat space-time is left behind.