English

G-Bounce

High Energy Physics - Theory 2011-11-14 v2 Cosmology and Nongalactic Astrophysics General Relativity and Quantum Cosmology

Abstract

We present a wide class of models which realise a bounce in a spatially flat Friedmann universe in standard General Relativity. The key ingredient of the theories we consider is a noncanonical, minimally coupled scalar field belonging to the class of theories with Kinetic Gravity Braiding / Galileon-like self-couplings. In these models, the universe smoothly evolves from contraction to expansion, suffering neither from ghosts nor gradient instabilities around the turning point. The end-point of the evolution can be a standard radiation-domination era or an inflationary phase. We formulate necessary restrictions for Lagrangians needed to obtain a healthy bounce and illustrate our results with phase portraits for simple systems including the recently proposed Galilean Genesis scenario.

Keywords

Cite

@article{arxiv.1109.1047,
  title  = {G-Bounce},
  author = {Damien A. Easson and Ignacy Sawicki and Alexander Vikman},
  journal= {arXiv preprint arXiv:1109.1047},
  year   = {2011}
}

Comments

28 pages. v2 reflects version accepted for publication in JCAP. References and minor comments added

R2 v1 2026-06-21T19:00:11.406Z