Criticality and Big Brake singularities in the tachyonic evolutions of closed Friedmann universes with cold dark matter

TL;DR

This paper investigates the evolution of closed Friedmann universes with tachyon fields and cold dark matter, identifying critical behaviors like Big Brake singularities and novel singularity-avoiding evolutions.

Contribution

It introduces a classification of tachyon-driven universe evolutions, including new singularity-avoiding scenarios and critical evolutions leading to Big Brake singularities.

Findings

Some evolutions lead to de Sitter attractors.

Others proceed through pseudo-tachyonic regimes into singularities.

Critical evolutions result in Big Brake singularities.

Abstract

The evolution of a closed Friedmann universe filled by a tachyon scalar field with a trigonometric potential and cold dark matter (CDM) is investigated. A subset of the evolutions consistent to 1$\sigma $ confidence level with the Union 2.1 supernova data set is identified. The evolutions of the tachyon field are classified. Some of them evolve into a de Sitter attractor, while others proceed through a pseudo-tachyonic regime into a sudden future singularity. Critical evolutions leading to Big Brake singularities in the presence of CDM are found and a new type of cosmological evolution characterized by singularity avoidance in the pseudo-tachyon regime is presented.