String inspired effective Lagrangian and Inflationary Universe

TL;DR

This paper explores a string-inspired effective Lagrangian involving graviton and dilaton fields, demonstrating through numerical solutions that it can produce an inflationary universe with time measured by the dilaton, independent of additional self-interactions.

Contribution

It introduces a string-inspired effective Lagrangian that naturally leads to an inflationary universe without requiring ad-hoc dilaton self-interactions.

Findings

Numerical solutions show an asymptotically inflationary universe.

Inflationary behavior is independent of added dilaton self-interactions.

Time evolution is governed by the dilaton field.

Abstract

We consider a string inspired effective Lagrangian for the graviton and dilaton, containing Einstein gravity at the zero slope limit. The numerical solution of the problem shows asymptotically an inflationary universe. The time is measured by the dilaton, as one expects. The result is independent of the introduction of ad-hoc self interactions for the dilaton field.