2024/04/09 by Goutam Mandal, Mandal, Goutam, Sudip Mishra +5
Physics and Astronomy · Earth and Planetary Sciences · #Cosmology and Gravitation Theories #Solar and Space Plasma Dynamics #Geophysics and Gravity Measurements
paper · pdf · doi:10.48550/arxiv.2404.07243
This paper presents an investigation of cosmological dynamics of tachyon fluid coupled to varyingmass dark matter particles in the background of spatially flat FLRW universe. The mechanism of varying mass particles scenario assumes the mass of the dark matter depends on time t through the scalar field ϕ in the sense that the decaying of dark matter reproduces the scalar field. First, we analyze the model from dynamical systems perspective by converting the cosmological evolution equations into an autonomous system of ordinary differential equations with a suitable transformation of variables. We choose the mass of dark matter as exponential function of scalar field and the exponential potential of the tachyon field is undertaken in such a way that the autonomous system is reduced in three dimensional form. The critical points obtained from the system are non-hyperbolic in nature. The center manifold theory is employed to discuss the nature of the critical points. Numerical investigation also carried out for some critical points. From this analysis, we obtain dust dominated decelerated transient phase of the universe followed by dark energy dominated scaling attractor alleviating the coincidence problem. Next, we perform the statefinder diagnostic approach to compare our model to ΛCDM and finally we study the evolution of the Hubble parameter and the distance modulus and compare this with observational data.