Density perturbations in the ekpyrotic scenario
Open accessAbstract
We study the generation of density perturbations in the ekpyrotic scenario for the early universe, including gravitational backreaction. We expose interesting subtleties that apply to both inflationary and ekpyrotic models. Our analysis includes a detailed proposal of how the perturbations generated in a contracting phase may be matched across a ``bounce'' to those in an expanding hot big bang phase. For the physical conditions relevant to the ekpyrotic scenario, we reobtain our earlier result of a nearly scale-invariant spectrum of energy density perturbations. We find that the perturbation amplitude is typically small, as desired to match observation.
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Each of the other cosmological scenarios (pre-Big-Bang, ekpyrotic/cyclic, Aguirre-Gratton, and Bojowald loop quantum gravity) invokes special low-entropy conditions on some Cauchy surface, either asymptotically in the far past or at some moment of minimum size for the universe.
“To the best of our understanding, each of these proposals invokes special low-entropy conditions on some Cauchy surface, either asymptotically in the far past or at some moment of minimum size for the universe.”
From Spontaneous inflation and the origin of the arrow of time (2004) · cites this paper as [96]
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Research works printed but not linked: 12
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Komatsu, E., Dunkley, J., Nolta, M. R., Bennett, C. L., Gold, B., Hinshaw, G., Jarosik, N., Larson, D., Limon, M., Page, L., et al. (2009) · The Astrophysical Journal Supplement Series · doi:10.1088/0067-0049/180/2/330 · Cited by 5,786 · see citing works
Towards a nonsingular bouncing cosmology
Cai, Y.-F., Easson, D. A., & Brandenberger, R. (2012) · Journal of Cosmology and Astroparticle Physics · doi:10.1088/1475-7516/2012/08/020 · Cited by 439 · see citing works
Ekpyrotic and Cyclic Cosmology
Lehners, J.-L. (2008) · Physics Reports · doi:10.1016/j.physrep.2008.06.001 · Cited by 381 · see citing works
Spontaneous inflation and the origin of the arrow of time
Carroll, S. M., & Chen, J. (2004) · arXiv · doi:10.48550/arxiv.hep-th/0410270 · Cited by 135 · see citing works
- Authors
- Khoury, J., Ovrut, B. A., Steinhardt, P. J., & Turok, N.
- Affiliations
- Princeton University (US)
- Venue
- Physical Review D
- Publisher
- American Physical Society (APS)
- Published
- 2002-08-26
- Volume
- 66
- Issue
- 4
- ISSN
- 0556-2821 (ISSN-L)
- 1089-4918
- OpenAlex
- W2072375180
- Cited by
- 263
- References
- 0
- Citations by year
- 2026: 1 · 2025: 1 · 2024: 11 · 2023: 3 · 2022: 3 · 2021: 4 · 2020: 7 · 2019: 2 · 2018: 10 · 2017: 4 · 2016: 9 · 2015: 9 · 2014: 9 · 2013: 13 · 2012: 19
- FWCI
- 16.34
- Type
- journal article
- Language
- en
- Open access
- green
- arxiv.org
- Locations
- Physical review. D. Particles, fields, gravitation, and cosmology/Physical review. D. Particles and fields (publishedVersion)
- arXiv (Cornell University) (submittedVersion)
- CERN Document Server (European Organization for Nuclear Research) (submittedVersion)
- arXiv (Cornell University)
- Funders
- U.S. Department of Energy (FG0291ER40671)
- Natural Sciences and Engineering Research Council of Canada
- Topics
- Physical Sciences › Physics and Astronomy › Astronomy and Astrophysics › Cosmology and Gravitation Theories
- Physical Sciences › Physics and Astronomy › Statistical and Nonlinear Physics › Noncommutative and Quantum Gravity Theories
- Physical Sciences › Physics and Astronomy › Nuclear and High Energy Physics › Black Holes and Theoretical Physics
- Keywords
- density perturbations, gravitational backreaction, bounce, contracting phase, scale-invariant spectrum, energy density perturbations, early universe, inflation (cosmology), perturbation amplitude
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