Stasis in an expanding universe: A recipe for stable mixed-component cosmological eras

Dienes, Keith R.; Heurtier, Lucien; Huang, Fei; Kim, Doojin; Tait, Tim M. P.; Thomas, Brooks

Abstract

One signature of an expanding universe is the time variation of the cosmological abundances of its different components. For example, a radiation-dominated universe inevitably gives way to a matterdominated universe, and critical moments such as matter-radiation equality are fleeting. In this paper, we point out that this lore is not always correct and that it is possible to obtain a form of “stasis” in which the relative cosmological abundances Ωi of the different components remain unchanged over extended cosmological epochs, even as the universe expands. Moreover, we demonstrate that such situations are not fine-tuned but are actually global attractors within certain cosmological frameworks, with the universe naturally evolving toward such long-lasting periods of stasis for a wide variety of initial conditions. The existence of this kind of stasis therefore gives rise to a host of new theoretical possibilities across the entire cosmological timeline, ranging from potential implications for primordial density perturbations, dark-matter production, and structure formation all the way to early reheating, early matter-dominated eras, and even the age of the Universe.

Citation

Dienes, K. R., Heurtier, L., Huang, F., Kim, D., Tait, T. M., & Thomas, B. (2022). Stasis in an expanding universe: A recipe for stable mixed-component cosmological eras. Physical Review D, 105(2), Article 023530. https://doi.org/10.1103/physrevd.105.023530

• Journal Article Type: Article
• Acceptance Date: Jan 3, 2022
• Online Publication Date: Jan 28, 2022
• Publication Date: Jan 15, 2022
• Deposit Date: Jun 15, 2022
• Publicly Available Date: Jun 15, 2022
• Journal: Physical Review D
• Print ISSN: 2470-0010
• Electronic ISSN: 2470-0029
• Publisher: American Physical Society
• Peer Reviewed: Peer Reviewed
• Volume: 105
• Issue: 2
• Article Number: 023530
• DOI: https://doi.org/10.1103/physrevd.105.023530
• Public URL: https://durham-repository.worktribe.com/output/1203897