Inflation Driven by Scalar-Neutrino Coupling in a Mass-Varying Neutrino Framework

TL;DR

This paper introduces a cosmological model where neutrino masses evolve through coupling with a scalar field that drives inflation, affecting inflation dynamics and unifying neutrino mass generation with early universe inflation.

Contribution

It presents a novel framework coupling neutrino mass evolution with inflation via a scalar field, incorporating different mass functions and analyzing their impact on inflationary dynamics.

Findings

Scalar-neutrino coupling modifies inflation potential

Hybrid coupling offers flexible inflation scenarios

Neutrino mass transition influences inflation duration

Abstract

We propose a cosmological framework in which neutrino masses evolve dynamically through coupling with a scalar field that simultaneously drives inflation. The neutrino mass is modeled as a power-law, exponential, or hybrid function of the scalar field, yielding an effective potential that includes neutrino backreaction. Starting from the Einstein-Hilbert action in a flat FLRW background, we derive the modified Friedmann and Klein Gordon equations incorporating this coupling. Using the Fermi-Dirac integrals, we account for the continuous transition of neutrinos from relativistic to non-relativistic regimes. The inflationary dynamics are analyzed via the slow roll parameters derived from the effective potential. Our results show that the scalar neutrino coupling alters the potential slope and curvature, thereby influencing the duration of inflation. The hybrid coupling form provides the most flexible realization, unifying neutrino mass generation with early universe inflation within a single scalar field framework.