Back-Reaction to Dilaton-Driven Inflation

TL;DR

This paper calculates the first-order back-reaction effects during dilaton-driven inflation, showing they are significant, favor exit to a standard cosmological phase, and differ from pure de-Sitter or power-law inflation cases.

Contribution

It provides the first computation of back-reaction effects in dilaton-driven inflation, highlighting their non-vanishing nature and impact on the inflationary exit.

Findings

Back-reaction is non-zero and significant.

Effect favors transition to a Friedmann-Robertson-Walker phase.

One-loop effects are of order _P^2H^2(t).

Abstract

We compute the leading-order back-reaction to dilaton-driven inflation, due to graviton, dilaton and gauge-boson production. The one-loop effect turns out to be non-vanishing (unlike the case for pure de-Sitter and for power-law inflation), to be of relative order $\ell_P^2H^2(t)$, and to have the correct sign for favouring the exit to a FRW phase.