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 Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

The following issue is addressed: how the addition of a Gauss-Bonnet term(generically coming from most fundamental theories, as string and M theories),to a viable model, can change the specific properties, and even the physicalnature, of the corresponding cosmological solutions? Specifically, brand neworiginal dark energy models are obtained in this way with quite interestingproperties, which exhibit, in a unified fashion, the three distinguishedpossible cosmological phases corresponding to phantom matter, quintessence, andordinary matter, respectively. A model, in which the equation of stateparameter, $w$, is a function of time, is seen to lead either to a singularityof the Big Rip kind or to a bouncing solution which evolves into a de Sitteruniverse with $w=-1$. Moreover, new Gauss-Bonnet modified gravity models withbouncing behavior in the early stages of the universe evolution are obtainedand tested for the validity and stability of the corresponding solutions. Theyallow for a remarkably natural, unified description of a bouncing behavior atearly times and accelerated expansion at present.

Gauss-Bonnet modified gravity models with bouncing behavior