Conformal inflation with chameleon coupling

TL;DR

This paper explores how a chameleon-like inflaton coupling to heavy matter affects inflation dynamics, attractor behavior, and observable parameters, revealing new inflationary regimes and suppression of entropy modes.

Contribution

It introduces a novel chameleon coupling in conformal inflation models, showing its impact on inflation duration, observables, and entropy mode suppression.

Findings

New attractor behaviors depending on coupling sign

Prolonged inflation scenarios identified

Strong suppression of entropy modes during inflation

Abstract

We investigate the possibility that the inflaton, in particular in conformal inflation models, is also a chameleon, i.e. that it couples to the energy density of some heavy non-relativistic matter present during inflation. We find new and interesting attractor behaviours, either prolonging inflation, or changing the observables $n_s,r$, depending on the sign of the chameleon coupling exponent. We also check that the chameleon coupling with the heavy matter field strongly suppress entropy modes during inflation.