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Title: Dissipative Boltzmann-Robertson-Walker cosmologies

The equations governing a flat Robertson-Walker cosmological model containing a dissipative Boltzmann gas are integrated numerically. The bulk viscous stress is modeled using the Eckart and Israel-Stewart theories of dissipative relativistic fluids; the resulting cosmologies are compared and contrasted. The Eckart models are shown to always differ in a significant quantitative way from the Israel-Stewart models. It thus appears inappropriate to use the pathological (nonhyperbolic) Eckart theory for cosmological applications. For large bulk viscosities, both cosmological models approach asymptotic nonequilibrium states; in the Eckart model the total pressure is negative, while in the Israel-Stewart model the total pressure is asymptotically zero. The Eckart model also expands more rapidly than the Israel-Stewart models. These results suggest that bulk-viscous'' inflation may be an artifact of using a pathological fluid theory such as the Eckart theory.
Authors:
;  [1]
  1. (Department of Physics, Montana State University, Bozeman, Montana 59717 (US))
Publication Date:
OSTI Identifier:
5796013
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review, D (Particles Fields); (USA); Journal Volume: 43:10
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; COSMOLOGICAL MODELS; UNIVERSE; COSMIC GASES; BOLTZMANN STATISTICS; DISSIPATION FACTOR; GRAVITATIONAL FIELDS; METRICS; RELATIVITY THEORY; THERMODYNAMIC PROPERTIES; VISCOUS FLOW; FIELD THEORIES; FLUID FLOW; FLUIDS; GASES; GENERAL RELATIVITY THEORY; MATHEMATICAL MODELS; PHYSICAL PROPERTIES 640106* -- Astrophysics & Cosmology-- Cosmology; 657002 -- Theoretical & Mathematical Physics-- Classical & Quantum Mechanics