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arXiv · 0806.0642

Thermodynamics of k-essence

Neven Bilic
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Abstract

We discuss thermodynamic properties of dark energy using the formalism of field theory at finite temperature. In particular, we apply our formalism to a purely kinetic type of k-essence. We show quite generally that the entropy associated with dark-energy is always equal or greater than zero. Hence, contrary to often stated claims, a violation of the null energy condition (phantom dark energy) does not necessarily yield a negative entropy. In addition, we find that the thermal fluctuations of a k-essence field may be represented by a free boson gas with an effective number of degrees of freedom equal to c_s^{-3}.

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Neven Bilic. 2008-11-14. Thermodynamics of k-essence. https://doi.org/10.1103/physrevd.78.105012

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