Closed String Tachyon Condensation and Worldsheet Inflation

TL;DR

This paper explores how closed string tachyon condensation can induce inflationary cosmology on the worldsheet, providing models that simulate different inflation scenarios and offer insights into the quantum origins of inflation.

Contribution

It introduces Liouville gravity models coupled to matter that can reproduce various inflationary phases and serve as a testing ground for inflationary theories.

Findings

Models exhibit pure de Sitter and slow-roll inflation

Provides a framework for quantum creation of cosmological spacetimes

Offers explanations for the onset and exit of inflation

Abstract

Closed string tachyon condensation in spacetime generates potentials on the worldsheet that model two-dimensional inflationary cosmology. These models illustrate and elucidate a variety of aspects of inflation, in particular the generation of quantum fluctuations and their back-reaction on geometry. We exhibit a class of Liouville gravity models coupled to matter that can exhibit, for example: (a) pure de Sitter gravity; (b) slow-roll inflation; (c) topological inflation; and (d) graceful exit into an FRW phase. The models also provide a quantitative testing ground for ideas about the origin of inflation, such as the various `no-boundary/tunnelling' proposals, and the `eternal/chaotic' inflationary scenario. We suggest an alternative mechanism for quantum creation of cosmological spacetimes which, in the context of the model, provides a natural explanation for why the typical FRW cosmology at large scales underwent a period of inflation at small scale.