Can an interacting varying Chaplygin gas and tachyonic matter accelerate Universe?

TL;DR

This paper explores how interactions between varying Chaplygin gas and tachyonic matter can lead to accelerated universe expansion and analyzes the resulting future singularities under different interaction scenarios.

Contribution

It introduces specific interaction forms between dark energy and dark matter and examines their effects on cosmic acceleration and singularity types.

Findings

Non-interacting model predicts Type II or IV singularities.

Certain interactions induce Type V singularity.

Scale factor forms allow analytical solutions without explicit potential forms.

Abstract

In this paper a possibility to accelerated the expansion of the large scale universe due to interacting varying Chaplygin gas of a specific form and a tachyonic matter is considered. A specific form of the potential and appropriate values of the parameters allow to obtain early tachyonic dark matter with $\omega_{T} \approx 0$ in recent Universe as well. On the other hand, related to the structure of the field equations describing the dynamics of the background we assumed the form of non-gravitational interaction to be given in advance. A sing changeable interaction between dark energy and dark matter is also included due to a huge interest towards it in recent literature. Possible future finite time singularities for cansidered models have been determined to finalize the paper. The study shows that in case of non-interacting model, the fate of the Universe will be either Type II~(The Sudden Singularity), or Type IV~(Generalized Sudden Singularity) singularity. On the other hand, the consideration of $Q=3 b H \rho_{de}$ non-gravitational interaction in addition to Type II and Type IV singularities will induce also Type V~($\omega$-singularity) singularity. Whilst in the model with $Q=3 b q H \rho_{de}$ non-gravitational interaction only Type IV singularity will be observed. Moreover, $2$ forms of the scale factor has been considered separately allowing analytically obtain the behavior of the cosmological parameters without specifying an explicit form of the potential for tachyonic matter.