| Full text | |
| Author(s): |
Total Authors: 2
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| Affiliation: | [1] Univ Sao Paulo, Dept Astron, BR-05508900 Sao Paulo - Brazil
Total Affiliations: 1
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| Document type: | Journal article |
| Source: | Physics Letters B; v. 669, n. 5, p. 266-270, NOV 27 2008. |
| Web of Science Citations: | 48 |
| Abstract | |
The thermodynamic properties of dark energy fluids described by an equation of state parameter omega = p/rho are rediscussed in the context of FRW type geometries. Contrarily to previous claims, it is argued here that the phantom regime omega < -1 is not physically possible since that both the temperature and the entropy of every physical fluids must be always positive definite. This means that one cannot appeal to negative temperature in order to save the phantom dark energy hypothesis as has been recently done in the literature. Such a result remains true as long as the chemical potential is zero. However, if the phantom fluid is endowed with a non-null chemical potential, the phantom field hypothesis becomes thermodynamically consistent, that is, there are macroscopic equilibrium states with T > 0 and S > 0 in the course of the Universe expansion. (C) 2008 Elsevier B.V. All rights reserved. (AU) | |
| FAPESP's process: | 04/13668-0 - Cosmology in the era of precision: dark energy, dark matter and background cosmic radiation |
| Grantee: | Jose Ademir Sales de Lima |
| Support Opportunities: | Research Projects - Thematic Grants |