Nonsingular Decaying Vacuum Cosmology and Entropy Production

Abstract

The thermodynamic behavior of a decaying vacuum cosmology describing the entire cosmological history evolving between two extreme (early and late time) de Sitter eras is investigated. The thermal evolution from the early de Sitter to the radiation phase is discussed in detail. The temperature evolution law and the increasing entropy function are analytically determined. The entropy of the effectively massless particles is initially zero but evolves continuously to the present day maximum value within the current Hubble radius, $S_0\sim 10^{88}$ in natural units. By using the Gibbons-Hawking temperature relation for the de Sitter spacetime, it is found that the ratio between the primeval and the late time vacuum energy densities is ${\rho }_{vI}/{\rho }_{v0}\sim 10^{123}$, as required by some naive estimates from quantum field theory.

12 pages in free style (some discussion added in the conclusions), 2 figures, accepted for publication in General Relativity and Gravitation

References in corpus (15)

• Dynamics of dark energy
• Primordial Nucleosynthesis in the Precision Cosmology Era
• Dark energy: a quantum fossil from the inflationary Universe?
• Dynamical vacuum energy in the expanding Universe confronted with observations: a dedicated study
• Hubble expansion and structure formation in the "running FLRW model" of the cosmic evolution
• Scalar-field-dominated cosmology with a transient accelerating phase
• Vacuum models with a linear and a quadratic term in H: structure formation and number counts analysis
• Entropy evolution of universes with initial and final de Sitter eras
• Gravitationally Induced Particle Production: Thermodynamics and Kinetic Theory
• What is the entropy of the universe?
• Cosmological implications and structure formation from a time varying vacuum
• A viable Starobinsky-like inflationary scenario in the light of Planck and BICEP2 results
• From inflation to late time acceleration with a decaying vacuum coupled to radiation or matter
• Upper and Lower Bounds on Gravitational Entropy
• Dark matter, dark energy and the time evolution of masses in the Universe

Cited by in corpus (5)

• Vacuum models with a linear and a quadratic term in H: structure formation and number counts analysis
• Vacuum dynamics in the Universe versus a rigid $\Lambda =$const
• Will-Nordtvedt PPN formalism applied to renormalization group extensions of general relativity
• Matter-Antimatter Asymmetry Induced by a Running Vacuum Coupling
• Implications of Dynamical Dark Energy in the expansion of the Universe and the Structure Formation