Brane tachyon dynamics

TL;DR

This paper studies the dynamics of tachyon fields on DGP branes with exponential and inverse power law potentials, revealing quasi-attractor behavior and conditions for crossing the phantom divide in dark energy models.

Contribution

It introduces the analysis of tachyon dynamics on DGP branes with specific potentials, highlighting quasi-attractor behavior and phantom divide crossing conditions.

Findings

Quasi-attractor behavior leads to slow-roll inflation-like phase.

EOS of dark energy can cross the phantom divide in certain branches.

Different potentials exhibit distinct crossing behaviors.

Abstract

The dynamics of a tachyon attached to a Dvali, Gabadadze and Porrati (DGP) brane is investigated. Exponential potential and inverse power law potential are explored, respectively. The quasi-attractor behavior, for which the universe will eventually go into a phase similar to the slow-roll inflation, is discovered in both cases of exponential potential and inverse power law potential. The equation of state (EOS) of the virtual dark energy for a single scalar can cross the phantom divide in the branch $\theta=-1$ for both potentials, while the EOS of the virtual dark energy for a single scalar can not cross this divide in the branch $\theta=1$.