The aim of this paper is to compare the evolution of viscous cosmological models for three different constitutive equations for the viscous pressure σ, namely: Eckart theory (σ=-ξμuμ), Maxwell-Cattaneo theory (σ+τσ=-ξμuμ), and generalized second-order Israel-Stewart theory (σ+τσ=-ξμuμ- 12ξσTρuμμ(vτTξ)). In the last case, the nonlinear terms may be interpreted as a consequence of nonlinear equations of state for absolute temperature and thermodynamic pressure. We show that the nonlinear terms of the latter equation are compatible with a viscosity-driven inflationary expansion. © 1993 The American Physical Society.
|Journal||Physical Review D|
|Publication status||Published - 1 Jan 1993|