Dynamical analysis of generalized Galileon cosmology

TL;DR

This paper conducts a detailed dynamical analysis of generalized Galileon cosmology, showing that it does not produce new stable late-time solutions beyond standard quintessence and that Galileons' effects vanish in the universe's future.

Contribution

It provides a comprehensive dynamical analysis of generalized Galileon models, highlighting their lack of new stable solutions and the independence of observables from Galileon terms at late times.

Findings

No new stable late-time solutions beyond quintessence.

Galileons may persist or disappear depending on parameters.

Observables are unaffected by Galileon terms at late times.

Abstract

We perform a detailed dynamical analysis of generalized Galileon cosmology, incorporating also the requirements of ghost and instabilities absence. We find that there are not any new stable late-time solutions apart from those of standard quintessence. Furthermore, depending on the model parameters the Galileons may survive at late times or they may completely disappear by the dynamics, however the corresponding observables are always independent of the Galileon terms, determined only by the usual action terms. Thus, although the Galileons can play an important role at inflationary or at recent times, in the future, when the universe will asymptotically reach its stable state, they will not have any effect on its evolution.