Analysis cosmological tachyon and fermion model and observation data constraints

TL;DR

This paper investigates a cosmological model combining tachyon and fermion fields with a barotropic equation of state, analyzing its stability, exact solutions, and observational constraints, revealing a transition from matter dominance to de-Sitter expansion.

Contribution

The study introduces a tachyonization method for fermion-tachyon cosmological models, providing stability analysis, exact solutions, and observational data comparison for the first time.

Findings

Model transitions from matter-dominated to de-Sitter universe.

Model is stable at barotropic index γ₀=0.00744.

Fits observational data within stability constraints.

Abstract

In this work we investigate a cosmological model with the tachyon and fermion fields with barotropic equation of state, where pressure $p$, energy density $\rho$ and barotropic index $\gamma$ are related by the relation $p=(\gamma-1)\rho$. We applied the tachyonozation method which allows to consider cosmological model with the fermion and the tachyon fields, driven by special potential. In this paper, tachyonization model was defined from the stability analysis and exact solution standard of the tachyon field. Analysis of the solution via statefinder parameters illustrated that our model in fiducial points with deceleration parameter $q = 0.5$ and statefinder $r = 1$ which corresponds to the matter dominated universe (SCDM) but, ends its evolution at a point in the future $(q =-1, \ r = 1)$ which corresponds to the de-Sitter expansion. Comparison of the model parameters with the cosmological observation data demonstrate, that our proposed cosmological model is stable at barotropic index $\gamma_0=0.00744$.