2003/05/01 by José Antonio Belinchón, JOSÉ ANTONIO BELINCHÓN, Indrajit Chakrabarty +1 · 3 citations
Physics and Astronomy · #Cosmology and Gravitation Theories #Dissipative system #Equation of state #Extended irreversible thermodynamics #Galaxies: Formation, Evolution, Phenomena #Relaxation (psychology) #Statistical Mechanics and Entropy #Symmetry (geometry) #Uniqueness #Viscosity #Viscous liquid #Volume viscosity #gr-qc
paper · pdf · doi:10.1142/s0218271803003402
published in International Journal of Modern Physics D 12(05), 861-883 (World Scientific) · 28 pages, RevTeX4
openalex publication_date 2003/05/01 · arxiv created 2004/04/09 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We study the evolution of a flat Friedmann–Robertson–Walker Universe, filled with a bulk viscous cosmological fluid, in the presence of time varying "constants." The dimensional analysis of the model suggests a proportionality between the bulk viscous pressure of the dissipative fluid and the energy density. Using this assumption and with the choice of the standard equations of state for the bulk viscosity coefficient, temperature and relaxation time, the general solution of the field equations can be obtained, with all physical parameters having a power-law time dependence. The symmetry analysis of this model, performed using Lie group techniques, confirms the uniqueness of the solution for this functional form of the bulk viscous pressure. In order to find another possible solution we relax the hypotheses and assume a concrete functional dependence for the "constants."