1997/03/31 by E. Gunzig, E Gunzig, Roy Maartens +3 · 3 citations
Physics and Astronomy · #Advanced Thermodynamics and Statistical Mechanics #Black Holes and Theoretical Physics #Cosmology and Gravitation Theories #astro-ph
paper · pdf · doi:10.1088/0264-9381/15/4/014
published as Class.Quant.Grav.15:923-932,1998 · Substantially revised, with new results; to appear in Class. Quantum Grav.; 12 pages Latex (ioplppt style)
arxiv created 1997/12/03 · openalex publication_date 1998/04/01 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We present a simple and thermodynamically consistent cosmology with a phenomenological model of quantum creation of radiation due to vacuum decay. Thermodynamics and Einstein’s equations lead to an equation in which H is determined by the particle number N. The model is completed by specifying the particle creation rate Γ = ˙ N/N, which leads to a second-order evolution equation for H. We propose a simple Γ that is naturally defined and that conforms to the thermodynamical conditions: (a) the entropy production rate starts at a maximum; (b) the initial vacuum (for radiation) is a non-singular regular vacuum; and (c) the creation rate is initially higher than the expansion rate H, but then falls below H. The evolution equation for H then has a remarkably simple exact solution, in which a non-adiabatic inflationary era exits smoothly to the radiation era, without a reheating transition. For this solution, we give exact expressions for the cosmic scale factor, energy density of radiation and vacuum, temperature, entropy and super-horizon scalar perturbations. PACS numbers: 9880C, 9880H, 9530T, 0540 1.