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

Journal Article · 27 January 2022 · Physical Review. D.

DOI: https://doi.org/10.1103/physrevd.105.023530 · OSTI ID:1980010

Dienes, Keith R.  ^[1]; Heurtier, Lucien  ^[2]; Huang, Fei  ^[3]; Kim, Doojin  ^[4]; Tait, Tim M. P.  ^[5]; Thomas, Brooks  ^[6]

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1. University of Arizona, Tucson, AZ (United States); University of Maryland, College Park, MD (United States); OSTI
2. Durham University (United Kingdom)
3. Chinese Academy of Sciences, Beijing (China); University of California, Irvine, CA (United States)
4. Texas A & M University, College Station, TX (United States)
5. University of California, Irvine, CA (United States)
6. Lafayette College, Easton, PA (United States)

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 matter-dominated 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 $$Ω_i$$ of the different components remain unchanged over extended cosmological epochs, even as the universe expands. Moreover, here 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.

• Research Organization: Texas A & M University, College Station, TX (United States); University of Arizona, Tucson, AZ (United States)
• Sponsoring Organization: Chinese Academy of Sciences; FG02-13ER41976 (NSF); International Postdoctoral Exchange Fellowship Program; National Natural Science Foundation of China; National Science Foundation (NSF); Science and Technology Facilities Council (STFC); USDOE Office of Science (SC)
• Grant/Contract Number: SC0009913; SC0010813
• OSTI ID: 1980010
• Journal Information: Physical Review. D., Journal Name: Physical Review. D. Journal Issue: 2 Vol. 105; ISSN 2470-0010
• Publisher: American Physical Society (APS)Copyright Statement
• Country of Publication: United States
• Language: English