Nonsingular Dilaton Cosmology

TL;DR

This paper explores nonsingular cosmological solutions within dilaton gravity, demonstrating a bouncing universe scenario that transitions smoothly from contraction to expansion, avoiding singularities.

Contribution

It introduces a specific higher derivative term in dilaton gravity leading to all solutions being nonsingular and describes a bouncing universe model.

Findings

All solutions are nonsingular.

Existence of a bouncing universe from contraction to expansion.

Compatible with pre-big-bang initial conditions.

Abstract

We study spatially homogeneous and isotropic solutions to the equations of motion derived from dilaton gravity, in the presence of a special combination of higher derivative terms in the gravitational action. All solutions are nonsingular. For initial conditions resembling those in the pre-big-bang scenario, there are solutions corresponding to a spatially flat, bouncing Universe originating in a dilaton-dominated contracting phase and emerging as an expanding Friedmann Universe.