TY - JOUR
T1 - Stasis in an expanding universe
T2 - A recipe for stable mixed-component cosmological eras
AU - Dienes, Keith R.
AU - Heurtier, Lucien
AU - Huang, Fei
AU - Kim, Doojin
AU - Tait, Tim M.P.
AU - Thomas, Brooks
N1 - Funding Information:
The research activities of K. R. D. are supported in part by the U.S. Department of Energy under Grants DE-FG02-13ER41976/DE-SC0009913 and also by the U.S. National Science Foundation through its employee IR/D program. The work of L. H. is supported in part by the United Kingdom Science and Technology Facilities Council (STFC) under Grant No. ST/P001246/1. The work of F. H. is supported in part by the International Postdoctoral Exchange Fellowship Program; by the National Natural Science Foundation of China under Grants No. 12025507, No. 11690022, No. 11947302, No. 12022514, and No. 11875003; by the Strategic Priority Research Program and Key Research Program of Frontier Science of the Chinese Academy of Sciences under Grants No. XDB21010200, No. XDB23010000, and No. ZDBS-LY-7003; and by the CAS project for Young Scientists in Basic Research YSBR-006. The work of D. K. is supported in part by the U.S. Department of Energy under Grant No. DE-SC0010813. The work of T. M. P. T. is supported in part by the U.S. National Science Foundation under Grant No. PHY-1915005. The research activities of B. T. are supported in part by the U.S. National Science Foundation under Grant No. PHY-2014104. The opinions and conclusions expressed herein are those of the authors and do not represent any funding agencies.
Publisher Copyright:
© 2022 us.
PY - 2022/1/15
Y1 - 2022/1/15
N2 - 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 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.
AB - 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 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.
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U2 - 10.1103/PhysRevD.105.023530
DO - 10.1103/PhysRevD.105.023530
M3 - Article
AN - SCOPUS:85124123127
SN - 2470-0010
VL - 105
JO - Physical Review D
JF - Physical Review D
IS - 2
M1 - 023530
ER -