Implications of single field inflation in general cosmological scenarios on the nature of dark energy given the swampland conjectures

TL;DR

This paper explores how single field inflation models within modified cosmological scenarios can accommodate a dark energy equation of state different from -1, consistent with swampland conjectures, challenging previous incompatibilities.

Contribution

It demonstrates that modified cosmologies allow single field inflation to align with swampland conjectures while permitting diverse dark energy behaviors.

Findings

Dark energy equation of state can differ from -1 under swampland constraints.

Single field inflation remains compatible with swampland conjectures in modified cosmologies.

Observable distinctions between dark energy models are possible without step-function inflation assumptions.

Abstract

Swampland Conjectures have attracted quite some interest in the Cosmological Community. They have been shown to have wide ranging implications , like Constraints on Inflationary Models, Primordial Black Holes etc. to name a few. A particularly revealing insight on dark energy also shows that one can have the dark energy equation of state for a quintessence scenario to be signficantly different than -1 after one takes into account the refined dS conjecture. Another interesting issue with the swampland conjectures is that they have been shown to be incompatible with single field inflationary models in GR based cosmology. In our previous work we have, however, showed that single field inflationary models are quite compatible with swampland conjectures in their usual string theoretic form in a large class of modified cosmological scenarios. Building on that work, we now show that in modified cosmological scenarios where the early universe expansion was driven by single field inflation , one can have the dark energy equation of state to be significantly different from -1 even if we just take into account the original dS conjecture, let alone the refined form of that. We thereby show that one does not need to apply a step function approach towards inflation in order to have an observable distinction between constant and non constant dark energy models in the context of the swampland conjectures.