Inflation and quintessence with nonminimal coupling

TL;DR

This paper explores how nonminimal coupling of scalar fields to gravity influences inflation and quintessence, showing it complicates standard models but can enable acceleration with unconventional potentials.

Contribution

It provides a detailed analysis of the effects of nonminimal coupling on cosmic acceleration, including the use of slow-roll approximation and conformal transformations.

Findings

NMC complicates achieving acceleration with usual potentials.

NMC can facilitate acceleration with unusual potentials.

The paper clarifies the physics of NMC in cosmological models.

Abstract

The nonminimal coupling (NMC) of the scalar field to the Ricci curvature is unavoidable in many cosmological scenarios. Inflation and quintessence models based on nonminimally coupled scalar fields are studied, with particular attention to the balance between the scalar potential and the NMC term in the action. NMC makes acceleration of the universe harder to achieve for the usual potentials, but it is beneficial in obtaining cosmic acceleration with unusual potentials. The slow-roll approximation with NMC, conformal transformation techniques, and other aspects of the physics of NMC are clarified.