Production of entropy and viscous damping of anisotropy in homogeneous cosmological models: Bianchi TypeI spaces.
Abstract
An investigation is conducted of world models in which strong initial anisotropies are damped out by viscous dissipation at temperatures lower than 1000 billion degrees K. The evolution of anisotropic flat spaces (Bianchi typeI spaces) during the lepton era and the subsequent plasma era is studied. It is assumed that the cosmological matter at each epoch can be represented by a fluid in thermal equilibrium. The damping characteristics in the case of the initial anisotropy are studied by means of a numerical integration of the Einstein equations. A large entropy production is found to be associated with the viscous damping, unless the universe was already quasiisotropic before the beginning of the lepton era. According to the results of the investigation, the present state of the universe appears to be determined by the physical properties of the cosmological matter itself.
 Publication:

Nuovo Cimento B Serie
 Pub Date:
 March 1978
 DOI:
 10.1007/BF02730343
 Bibcode:
 1978NCimB..44..228C
 Keywords:

 Anisotropic Media;
 Astronomical Models;
 Background Radiation;
 Big Bang Cosmology;
 Entropy;
 Universe;
 Viscous Damping;
 Einstein Equations;
 Energy Dissipation;
 Leptons;
 Numerical Integration;
 Astrophysics;
 Cosmological Models