A Cosmological Interpretation of Duality

TL;DR

This paper explores how duality symmetry in string cosmology implies a universe with a rebounding scale factor at the self-dual length, leading to equivalent universe scenarios and a maximum temperature.

Contribution

It demonstrates the cosmological implications of duality symmetry using a two-dimensional string cosmology model, revealing universe rebounds and equivalence of different scenarios.

Findings

Scale factor rebounds at self-dual length.

Four mathematically different but physically equivalent scenarios.

Presence of a maximum temperature in all evolutions.

Abstract

We study the cosmological meaning of duality symmetry by considering a two dimensional model of string cosmology. We find that as seen by an internal observer in this universe, the scale factor rebounds at the self-dual length. This rebound is a consequence of the adiabatic expansion. Furthermore, in this situation there are four mathematically different scenarios which describe physically equivalent universes which are in fact indistinguishable. We also stress that $R$-duality suffices to prove that all possible evolutions present a maximum temperature.