English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

This brief report studies the behavior of entropy in two recent models ofcosmic evolution by J.A.S. Lima, S. Basilakos, and F.E.M. Costa [Phys. Rev. D\underline{86}, 103534 (2012)], and J. A. S. Lima, S. Basilakos, and J.Sol\'{a} [arXiv:1209.2802]. Both start with an initial de Sitter expansion, gothrough the conventional radiation and matter dominated eras to be followed bya final and everlasting de Sitter expansion. In spite of their outwardsimilarities (from the observational viewpoint they are arbitrary close to theconventional $\Lambda$CDM model), they deeply differ in the physics behindthem. Our study reveals that in both cases the universe approachesthermodynamic equilibrium in the last de Sitter era in the sense that theentropy of the apparent horizon plus that of matter and radiation inside itincreases and is concave. Accordingly, they are consistent with thermodynamics.Cosmological models that do not approach equilibrium at the last phase of theirevolution appear in conflict with the second law of thermodynamics.

Entropy evolution of universes with initial and final de Sitter eras