More on Tachyon Cosmology in De Sitter Gravity

TL;DR

This paper explores rolling tachyon solutions in de Sitter gravity, showing they can produce inflation and require fine-tuning of the cosmological constant, with implications for string compactification.

Contribution

It provides new insights into tachyon-driven inflation in de Sitter space and establishes bounds on compactification volume, extending previous cosmological models.

Findings

Tachyon solutions can induce inflation with specific initial conditions.

The cosmological constant must be fine-tuned at the action level.

An upper bound on the compactification volume is derived.

Abstract

We aim to study rolling tachyon cosmological solutions in de Sitter gravity. The solutions are taken to be flat FRW type and these are not time-reversal symmetric. We find that cosmological constant of our universe has to be fine-tuned at the level of the action itself, as in KKLT string compactification. The rolling tachyon can give rise to required inflation with suitable choice of the initial conditions which include nonvanishing Hubble constant. We also determine an upper bound on the volume of the compactification manifold.