Chemical Potential and the Nature of the Dark Energy: The case of phantom

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dc.creatorLima, J. A. S.
dc.creatorPereira, S. H.
dc.date2008-01-02
dc.date.accessioned2026-07-07T11:54:56Z
dc.date.available2026-07-07T11:54:56Z
dc.descriptionThe influence of a possible non zero chemical potential $μ$ on the nature of dark energy is investigated by assuming that the dark energy is a relativistic perfect simple fluid obeying the equation of state (EoS), $p=ωρ$ ($ω<0, constant$). The entropy condition, $S \geq 0$, implies that the possible values of $ω$ are heavily dependent on the magnitude, as well as on the sign of the chemical potential. For $μ>0$, the $ω$-parameter must be greater than -1 (vacuum is forbidden) while for $μ< 0$ not only the vacuum but even a phantomlike behavior ($ω<-1$) is allowed. In any case, the ratio between the chemical potential and temperature remains constant, that is, $μ/T=μ_0/T_0$. Assuming that the dark energy constituents have either a bosonic or fermionic nature, the general form of the spectrum is also proposed. For bosons $μ$ is always negative and the extended Wien's law allows only a dark component with $ω< -1/2$ which includes vacuum and the phantomlike cases. The same happens in the fermionic branch for $μ<0$. However, fermionic particles with $μ>0$ are permmited only if $-1 < ω< -1/2$. The thermodynamics and statistical arguments constrain the EoS parameter to be $ω< -1/2$, a result surprisingly close to the maximal value required to accelerate a FRW type universe dominated by matter and dark energy ($ω\lesssim -10/21$).
dc.description7 pages, 5 figures
dc.identifierhttps://arxiv.org/abs/0801.0323
dc.identifierhttp://arxiv.org/abs/0801.0323
dc.identifierPhys.Rev.D78:083504,2008
dc.identifierdoi:10.1103/PhysRevD.78.083504
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/205087
dc.subjectAstrophysics
dc.titleChemical Potential and the Nature of the Dark Energy: The case of phantom
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