Unimodular Mimetic $F(R)$ Inflation

TL;DR

This paper introduces a novel unimodular-mimetic $F(R)$ gravity framework that addresses dark energy and dark matter issues, naturally supports accelerated expansion, and aligns with current cosmological observations.

Contribution

It develops a unified geometric model combining unimodular and mimetic gravity within $F(R)$ theories, providing inflationary scenarios consistent with observational data.

Findings

The model admits an accelerating universe evolution.

Constructed inflationary scenarios match Planck and BICEP2/Keck-Array data.

Addresses graceful exit via unstable de Sitter vacua.

Abstract

We propose the unimodular-mimetic $F(R)$ gravity theory, to resolve cosmological constant problem and dark matter problem in a unified geometric manner. We demonstrate that such a theory naturally admits accelerating universe evolution. Furthermore, we construct unimodular-mimetic $F(R)$ inflationary cosmological scenarios compatible with the Planck and BICEP2/Keck-Array observational data. We also address the graceful exit issue, which is guaranteed by the existence of unstable de Sitter vacua.