Nonsingular Decaying Vacuum Cosmology and Entropy Production

Understand

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.