2025/11/19 by Netto, J. M. Costa, Gonzalez, Javier E., Silva, H. H. B.
Physics and Astronomy · #Cosmology and Gravitation Theories #Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences #Gamma-ray bursts and supernovae #Pulsars and Gravitational Waves Research
paper · doi:10.48550/arxiv.2511.15828
openalex publication_date 2025/11/19 · openalex created_date 2025/11/23 · openalex updated_date 2026/07/28
In this work, we impose observational limits on the product of dark energy chemical potential, μ, and number density, n, at the present time in out-of-equilibrium models, considering that particles can be created or destroyed in the fluid at a rate Γ=3αH(a), where α is a constant and H(a)≡a/a is the Hubble parameter. We combine the bounds derived from the positivity of entropy and the second law of thermodynamics with observational constraints on the Chevallier-Polarski-Linder (CPL) and Barboza-Alcaniz (BA) parameterizations of the equation of state (EoS) of the component. We use Type Ia supernovae (SN Ia) data from Pantheon+; baryon acoustic oscillation (BAO) data from DESI DR2; and cosmic microwave background (CMB) measurements from Planck. For α>0 (particle creation), the thermodynamic restrictions yield only upper limits for the μ0n0 product, while in the case of α<0 (particle destruction) they establish both upper and lower limits, allowing for a range of values to be obtained. In both scenarios, however, we find that the chemical potential of dark energy must be negative, μ<0, which indicates a preference for the phantom regime. In particular, when α<0, it is noted that the thermodynamic bounds are simultaneously compatible only for very small absolute values of α, with α=-0.0002 being the limiting case and resulting in μ0n0(α=-0.0002)=-2.2-0.7+1.0 GeV/m3.