A Galileon Design of Slow Expansion: II

TL;DR

This paper explores slow expansion models originating from a static state, demonstrating they can produce scale-invariant perturbations without ghost instabilities using generalized Galileon theories.

Contribution

It introduces a classification of slow expansion evolutions from a static universe and shows their realization via ghost-free generalized Galileon Lagrangians.

Findings

Scale-invariant perturbations can be generated during slow expansion.

Evolutions are realizable with ghost-free generalized Galileon Lagrangians.

Models originate from a static initial state.

Abstract

We parameterize the evolutions of the slow expansion, which emerges from a static state in infinite past, into different classes. We show that the scale invariant adiabatical perturbation may be generated during these evolutions, and the corrsponding evolutions can be realized with generalized Galileon Lagrangians, in which there is not the ghost instability.