Stable Cosmic Time Crystals
High Energy Physics - Theory
2019-02-13 v2 General Relativity and Quantum Cosmology
Abstract
Cosmological time crystals are created when a scalar field moves periodically through phase space in a spatially flat Friedmann-Robertson-Walker spacetime due to the presence of a limit cycle. All such cosmological time crystals in the literature suffer from gradient instabilities occurring at Null Energy Condition violating phases where the square sound speed for cosmological perturbations becomes negative. Here we present stable cosmological time crystals. Our analysis suggests this new form of scalar matter--cosmic time crystals--may be considered as a physically viable cosmological matter source.
Keywords
Cite
@article{arxiv.1802.03693,
title = {Stable Cosmic Time Crystals},
author = {Damien A. Easson and Tucker Manton},
journal= {arXiv preprint arXiv:1802.03693},
year = {2019}
}
Comments
5 pages, 4 figures; matches version to appear in PRD