New Insights into Vacuum Cosmology from Thermal Dynamics

Recent research by P. E. M. Almeida, R. C. Santos, and J. A. S. Lima presents a new perspective on cosmology through their paper titled "From de Sitter to de Sitter: A Thermal Approach to Running Vacuum Cosmology and the Non-Canonical Scalar Field Description" (arXiv:2408.16911). The authors discuss the classical cosmological history between two extreme de Sitter vacuum solutions using Einstein's equations and non-equilibrium thermodynamics. They describe an initial non-singular de Sitter state characterized by a high energy scale, which is equal to or smaller than the reduced Planck mass. This state is deemed structurally unstable, with continuous creation of matter, energy, and entropy arising from an irreversible flow powered by primeval vacuum energy density.

The paper derives an analytical expression for the running vacuum from a thermal approach, which could provide solutions to longstanding puzzles and current observational challenges faced by the cosmic concordance model, typically driven by a rigid vacuum. Additionally, the authors model this scenario through a non-canonical scalar field, demonstrating that the resulting scalar field model serves as a faithful analytical representation of thermal running vacuum cosmology. This work may have significant implications for understanding the dynamics of the universe and addressing existing cosmological questions.