Geometrical Tachyon Dynamics in the Background of a Bulk Tachyon Field

TL;DR

This paper investigates the motion of a D3-brane influenced by a bulk tachyon in Type-0 string theory, revealing inflation at weak coupling and late-time acceleration linked to the bulk tachyon's behavior.

Contribution

It introduces a geometrical tachyon model modified by bulk tachyon effects, connecting brane dynamics with cosmological inflation and acceleration.

Findings

Inflation occurs at weak string coupling near the tachyon potential's top.

Late acceleration phase corresponds to the bulk tachyon approaching zero.

The geometrical tachyon potential is significantly affected by the bulk tachyon.

Abstract

We study the dynamics of a D3-brane moving in the background of a bulk tachyon field of a D3-brane solution of Type-0 string theory. We show that the dynamics on the probe D3-brane can be described by a geometrical tachyon field rolling down its potential which is modified by a function of the bulk tachyon and inflation occurs at weak string coupling, where the bulk tachyon condenses, near the top of the geometrical tachyon potential. We also find a late accelerating phase when the bulk tachyon asymptotes to zero which in the geometrical tachyon picture corresponds to the minimum of the geometrical potential.