Cosmological solutions in five dimensional Einstein-Maxwell-dilaton theory

TL;DR

This paper presents new exact, non-stationary cosmological solutions in five-dimensional Einstein-Maxwell-dilaton theory, showing how the universe's size evolves over time with various cosmological constant values.

Contribution

It introduces novel classes of solutions with two dilaton coupling constants, expanding understanding of five-dimensional cosmological models in Einstein-Maxwell-dilaton theory.

Findings

Solutions are almost regular everywhere.

Spatial size shrinks at early times and expands infinitely at late times.

Cosmological constant varies with dilaton coupling, being positive, zero, or negative.

Abstract

We construct new classes of exact cosmological solutions to five dimensional Einstein-Maxwell-dilaton theory with two coupling constants for the dilaton-Maxwell term and dilaton-cosmological constant term. All the solutions are non-stationary and the solutions that both coupling constants are non-zero are almost regular everywhere. The size of spatial section of the asymptotic metric shrinks to zero at early time and increases to infinitely large at very late time. The cosmological constant depends on the dilaton coupling constant and can take positive, zero or negative values.