2002/01/11 by J. A. S. Lima, Lima, J. A. S., J. A. Espichán Carrillo +1
Physics and Astronomy · #Astrophysics (astro-ph) #FOS: Physical sciences #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0201168
14 pages, 1 table, no figure, revtex
arxiv created 2002/01/11 · arxiv updated 2016/08/30
We study the thermodynamic behavior of a decaying scalar field coupled to a relativistic simple fluid. It is shown that if the decay products are represented by a thermalized bath, its temperature evolution law requires naturally a new phenomenological coupling term. This ``energy loss'' term is the product between the enthalpy density of the thermalized bath and the decay width of the scalar field. We also argue that if the field ϕ decays "adiabatically" some thermodynamic properties of the fluid are preserved. In particular, for a field decaying into photons, the radiation entropy production rate is independent of the specific scalar field potential V(ϕ), and the energy density ρ and average number density of photons n scale as ρ∼ T4 and n ∼ T3. To illustrate these results, a new warm inflationary scenario with no slow roll is proposed.