Quintessential inflation in Palatini f(R) gravity

Abstract

We investigate in detail a family of quintessential inflation models in the context of R+R 2 Palatini modified gravity. We find that successful inflation and quintessence are obtained with an inflaton scalar potential that is approximately quadratic in inflation and inverse quartic in quintessence. We show that corrections for the kination period due to Palatini modified gravity are subdominant, while the setup does not challenge constraints on modified gravity from solar system observations and microscopic experiments, in contrast to the metric case. We obtain concrete predictions regarding primordial tensors to be probed in the near future.

Quintessential inflation: A tale of emergent and broken symmetries

“…with M a constant with the dimension of mass and f (ϕ) a dimensionless runaway function of the cosmon field. This peculiar structure appears naturally in Palatini scalar-tensor and modified gravity scenarios involving Jordan-frame potentials proportional to the square of the non-minimal coupling to gravity [134] or R 2 corrections [135]. Given f (ϕ), this setting generates an inflationary plateau for f (ϕ) 1, while reducing to the canonical form (1) for f (ϕ)…”

A Review of Quintessential Inflation

“…Another important contribution of Dimopoulos is the introduction of the concept of warm quintessential inflation in [82], which is applied to the original Peebles-Vilenkin model, justifies the unification of early-and late-time acceleration and providing a very natural mechanism for reheating our universe. In the same way, an interesting idea is to consider quintessential inflation in the context of Palatini R 2 -gravity [83], adapting the well-known Starobinsky model to QI.…”

Introduction to Cosmic Inflation and Dark Energy

“…Recently, the framework of Palatini modified gravity has been utilised to study quintessential inflation in Ref. [18]. The Lagrangian density is…”