skip to main content
DOE PAGES title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: The coincidence problem and the Swampland conjectures in the Ijjas-Steinhardt cyclic model of the universe

Abstract

In the Ijjas-Steinhardt cyclic model, the universe passes through phases dominated by radiation, matter, and a dark energy scalar field, with the value of the scale factor increasing with each cycle. Since each cycle terminates in a finite time, it is straightforward to calculate the fraction of time that the universe spends in a state for which the matter and dark energy densities have comparable magnitudes; when this fraction is large, it can be taken as a solution of the coincidence problem. This solution of the coincidence problem requires a relatively short lifetime for each cycle, but unlike in the case of phantom models, there is no fixed upper bound on this lifetime. However, scalar field models satisfying the Swampland conjectures yield sufficiently short lifetimes to provide a satisfactory resolution of the coincidence problem.

Authors:
Publication Date:
Research Org.:
Vanderbilt Univ., Nashville, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC), High Energy Physics (HEP)
OSTI Identifier:
1567721
Alternate Identifier(s):
OSTI ID: 1599597
Grant/Contract Number:  
SC0019207
Resource Type:
Published Article
Journal Name:
Physics Letters B
Additional Journal Information:
Journal Name: Physics Letters B Journal Volume: 798 Journal Issue: C; Journal ID: ISSN 0370-2693
Publisher:
Elsevier
Country of Publication:
Netherlands
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; dark energy; swampland conjecture; cosmological constant coincidence problem; cyclic universe

Citation Formats

Scherrer, Robert J. The coincidence problem and the Swampland conjectures in the Ijjas-Steinhardt cyclic model of the universe. Netherlands: N. p., 2019. Web. doi:10.1016/j.physletb.2019.134981.
Scherrer, Robert J. The coincidence problem and the Swampland conjectures in the Ijjas-Steinhardt cyclic model of the universe. Netherlands. doi:10.1016/j.physletb.2019.134981.
Scherrer, Robert J. Fri . "The coincidence problem and the Swampland conjectures in the Ijjas-Steinhardt cyclic model of the universe". Netherlands. doi:10.1016/j.physletb.2019.134981.
@article{osti_1567721,
title = {The coincidence problem and the Swampland conjectures in the Ijjas-Steinhardt cyclic model of the universe},
author = {Scherrer, Robert J.},
abstractNote = {In the Ijjas-Steinhardt cyclic model, the universe passes through phases dominated by radiation, matter, and a dark energy scalar field, with the value of the scale factor increasing with each cycle. Since each cycle terminates in a finite time, it is straightforward to calculate the fraction of time that the universe spends in a state for which the matter and dark energy densities have comparable magnitudes; when this fraction is large, it can be taken as a solution of the coincidence problem. This solution of the coincidence problem requires a relatively short lifetime for each cycle, but unlike in the case of phantom models, there is no fixed upper bound on this lifetime. However, scalar field models satisfying the Swampland conjectures yield sufficiently short lifetimes to provide a satisfactory resolution of the coincidence problem.},
doi = {10.1016/j.physletb.2019.134981},
journal = {Physics Letters B},
number = C,
volume = 798,
place = {Netherlands},
year = {2019},
month = {11}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record
DOI: 10.1016/j.physletb.2019.134981

Save / Share: