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Entropy 2015, 17(9), 6318-6328;

Viscosity-Induced Crossing of the Phantom Barrier

Department of Energy and Process Engineering, Norwegian University of Science and Technology, N-7491 Trondheim, Norway
Academic Editor: Remo Garattini
Received: 31 July 2015 / Revised: 6 September 2015 / Accepted: 8 September 2015 / Published: 14 September 2015
(This article belongs to the Special Issue Entropy in Quantum Gravity and Quantum Cosmology)
Full-Text   |   PDF [204 KB, uploaded 14 September 2015]


We show explicitly, by using astrophysical data plus reasonable assumptions for the bulk viscosity in the cosmic fluid, how the magnitude of this viscosity may be high enough to drive the fluid from its position in the quintessence region at present time t = 0 across the barrier w = −1 into the phantom region in the late universe. The phantom barrier is accordingly not a sharp mathematical divide, but rather a fuzzy concept. We also calculate the limiting forms of various thermodynamical quantities, including the rate of entropy production, for a dark energy fluid near the future Big Rip singularity. View Full-Text
Keywords: cosmology; viscous cosmology; dark energy cosmology; viscous cosmology; dark energy
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited (CC BY 4.0).

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Brevik, I. Viscosity-Induced Crossing of the Phantom Barrier. Entropy 2015, 17, 6318-6328.

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