Stable Cosmic Time Crystals

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.

arXiv comment5 pages, 4 figures; matches version to appear in PRD

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Cited by in corpus (16)

• On the past-completeness of inflationary spacetimes
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• Inflation and late-time accelerated expansion driven by $k$-essence degenerate dynamics
• Self-Organized Higgs Criticality
• Eternal Universes
• On Quantum Simulation Of Cosmic Inflation
• Birth of de Sitter Universe from time crystal
• Classical and quantum time crystals in a levitated nanoparticle without drive
• Cosmological Time Crystals From Einstein-Cubic Gravities
• Scalar fields, localized structures and the Starobinsky model
• Cosmological Time Crystals from Gauss-Bonnet Gravity in Four Dimensions
• Smoking-gun signatures of bounce cosmology from echoes of relic gravitational waves
• Time crystals in primordial perturbations
• Cuscuton-like contribution to dark energy evolution
• Dark Energy from Time Crystals
• Cosmic acceleration from string induced Galileons