Dynamical Stability of Bulk Viscous Isotropic and Homogeneous Universe

Universe

Muhammad Sharif¹  Qanitah Ama-Tul-Mughani¹ 

[1] Department of Mathematics, University of the Punjab, Quaid-e-Azam Campus, Lahore-54590, Pakistan;

关键词: stability;    phase space analysis;    bulk viscosity;   

DOI  :  10.3390/universe5080185

来源: DOAJ

【 摘 要 】

In this paper, we study the phase space portrait of homogeneous and isotropic universe by taking different coupling functions between dark energy models and bulk viscous dark matter. The dimensionless quantities are introduced to establish an autonomous set of equations. To analyze the stability of the cosmos, we evaluate critical points and respective eigenvalues for different dynamical quantities. For bulk viscous matter and radiation in tachyon coupled field, these points show stable evolution when $\gamma \gg \delta$ but accelerated expansion of the universe for $\delta >\frac{1}{9}$ . The stability of the universe increases for some stationary points which may correspond to the late-time expansion for the coupled phantom field.

【 授权许可】

Unknown