Quintessential inflation from Lorentzian slow roll

D Benisty,E I Guendelman

doi:10.1140/epjc/s10052-020-8147-8

Abstract

From the assumption that the slow-roll parameter varepsilon has a Lorentzian form as a function of the e-fold number N, a successful model of a quintessential inflation is obtained, as succinctly studied in[1]. The form corresponds to the vacuum energy both in the inflationary and in the dark-energy epochs and satisfies the condition to climb from small values of varepsilon to 1 at the end of the inflationary epoch. We find the corresponding scalar quintessential inflationary potential with two flat regions. Moreover, a reheating mechanism is suggested with numerical estimation for the homogeneous evolution of the universe. The suggested mechanism is consistent with the BBN bound.

Highlights

These two regimes of accelerated expansion are treated independently
While the standard approach is to introduce some potential with slow-roll behavior, a successful model of quintessential inflation can be obtained from the ansatz of the slow-roll parameter as a function of the scale parameter itself [77–79], especially, with a Lorentzian ansatz [1]
We formulate the slow-roll parameter of the inflaton field in a Lorentzian form

Summary

Introduction

These two regimes of accelerated expansion are treated independently. It is both tempting and economical to think that there is a unique cause responsible for a quintessential inflation [47–76], which refers to unification of both concepts using a single scalar field. Consistency of the scenario requires that the new degree of freedom, namely the scalar field, should not interfere with the thermal history of the universe, and thereby it should be “invisible” for the entire evolution and reappear only around the present epoch, giving rise to late-time cosmic acceleration. We calculate the complete evolution of the universe from this ansatz. The plan of the work is as follows: in Sect.

Lorentzian ansatz

Scalar-field dynamics

Reheating

Late-time expansion

Conclusions