Inflation Deflation and Frame-Independence in String Cosmology

TL;DR

This paper explores how inflationary scenarios in string cosmology, when viewed through different frames, correspond to deflationary phases, offering a frame-independent understanding of early universe dynamics and addressing recent objections to superstring cosmology.

Contribution

It demonstrates the equivalence of inflation and deflation in different frames within string cosmology, providing a frame-independent perspective on early universe phenomena.

Findings

Inflationary scenarios in string cosmology correspond to deflation in the Einstein frame.

Key virtues of inflation are physically equivalent in the deflationary picture.

This frame-independence may address objections to superstring cosmology.

Abstract

The inflationary scenarios suggested by the duality properties of string cosmology in the Brans-Dicke (or String) frame are shown to correspond to accelerated contraction (deflation) when Weyl-transformed to the Einstein frame. We point out that the basic virtues of inflation (solving the flatness and horizon problems, amplifying vacuum fluctuations, etc.) have physically equivalent counterparts in the deflationary (Einstein-frame) picture. This could be the answer to some objections recently raised to superstring cosmology.