[Submitted on 2 Apr 2014 (v1), last revised 19 May 2014 (this version, v2)]
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Physicists Calculate Number of Parallel UniversesWhy does outer space look black?The universe is expanding, but what exactly is it expanding into?Ask a grown-up: where does the sky end?Authors:C. Wetterich
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Ask an AstronomerAbstract:We discuss cosmological models for an eternal universe. Physical observables show no singularity from the infinite past to the infinite future. While the universe is evolving, there is no beginning and no end - the universe exists forever. The early state of inflation is described in two different, but equivalent pictures. In the freeze frame the universe emerges from an almost static state with flat geometry. After entropy production it shrinks and "thaws" slowly from a "freeze state" with extremely low temperature. The field transformation to the second "big bang picture" (Einstein frame) is singular. This "field singularity" is responsible for an apparent singularity of the big bang. Furthermore, we argue that past-incomplete geodesics do not necessarily indicate a singularity or beginning of the universe. Proper time ceases to be a useful concept for physical time if particles become massless. We propose to define physical time by counting the number of zeros of a component of the wave function. This counting is independent of the choice of coordinates and frames, and applies to massive and massless particles alike.
| Comments: | Extended discussion of physical time, map between frames, limitation of proper time, incomplete geodesics in the Sitter space, graviton scattering, 17 pages, 2 figures |
| Subjects: | General Relativity and Quantum Cosmology (gr-qc); Cosmology and Nongalactic Astrophysics (astro-ph.CO); High Energy Physics - Theory (hep-th) |
| Cite as: | arXiv:1404.0535 [gr-qc] |
| (or arXiv:1404.0535v2 [gr-qc] for this version) | |
| https://doi.org/10.48550/arXiv.1404.0535 arXiv-issued DOI via DataCite | |
| Journalreference: | Phys. Rev. D 90, 043520 (2014) |
| Related DOI: | https://doi.org/10.1103/PhysRevD.90.043520 DOI(s) linking to related resources |
Submission history
From: Christof Wetterich [view email]
[v1] Wed, 2 Apr 2014 12:36:59 UTC (67 KB)
[v2] Mon, 19 May 2014 16:10:00 UTC (105 KB)
