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Friedmann cosmology with a generalized equation of state and bulk viscosity

Xin-He Meng·Jie Ren·Ming-Guang Hu
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Abstract

The universe media is considered as a non-perfect fluid with bulk viscosity and described by a more general equation of state. We assume the bulk viscosity is a linear combination of the two terms: one is constant, and the other is proportional to the scalar expansion $θ=3\dot{a}/a$. The equation of state is described as $p=(γ-1)ρ+p_0$, where $p_0$ is a parameter. This model can be used to explain the dark energy dominated universe. Different choices of the parameters may lead to three kinds of fates of the cosmological evolution: no future singularity, big rip, or Type III singularity of Ref. [S. Nojiri, S.D. Odintsov, and S. Tsujikawa, Phys. Rev. D \textbf{71}, 063004 (2005)].

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Xin-He Meng, Jie Ren, Ming-Guang Hu. 2005-09-09. Friedmann cosmology with a generalized equation of state and bulk viscosity. https://doi.org/10.1088/0253-6102%2F47%2F2%2F036

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