Cosmologies with turning points
We explore singularity-free and geodesically-complete cosmologies based on manifolds that are not quite Lorentzian. The metric can be either smooth everywhere or non-degenerate everywhere, but not both, depending on the coordinate system. The smooth metric gives an Einstein tensor that is first orde...
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| Format: | Article |
| Language: | English |
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Elsevier
2023-04-01
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| Series: | Physics Letters B |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S0370269323001363 |
| _version_ | 1797867696104144896 |
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| author | Bob Holdom |
| author_facet | Bob Holdom |
| author_sort | Bob Holdom |
| collection | DOAJ |
| description | We explore singularity-free and geodesically-complete cosmologies based on manifolds that are not quite Lorentzian. The metric can be either smooth everywhere or non-degenerate everywhere, but not both, depending on the coordinate system. The smooth metric gives an Einstein tensor that is first order in derivatives while the non-degenerate metric has a piecewise FLRW form. On such a manifold the universe can transition from expanding to contracting, or vice versa, with the Einstein equations satisfied everywhere and without violation of standard energy conditions. We also obtain a corresponding extension of the Kasner vacuum solutions on such manifolds. |
| first_indexed | 2024-04-09T23:44:16Z |
| format | Article |
| id | doaj.art-e637512972004590a692930ad2f705f9 |
| institution | Directory Open Access Journal |
| issn | 0370-2693 |
| language | English |
| last_indexed | 2024-04-09T23:44:16Z |
| publishDate | 2023-04-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Physics Letters B |
| spelling | doaj.art-e637512972004590a692930ad2f705f92023-03-18T04:40:11ZengElsevierPhysics Letters B0370-26932023-04-01839137802Cosmologies with turning pointsBob Holdom0Department of Physics, University of Toronto, Toronto, Ontario, M5S 1A7, CanadaWe explore singularity-free and geodesically-complete cosmologies based on manifolds that are not quite Lorentzian. The metric can be either smooth everywhere or non-degenerate everywhere, but not both, depending on the coordinate system. The smooth metric gives an Einstein tensor that is first order in derivatives while the non-degenerate metric has a piecewise FLRW form. On such a manifold the universe can transition from expanding to contracting, or vice versa, with the Einstein equations satisfied everywhere and without violation of standard energy conditions. We also obtain a corresponding extension of the Kasner vacuum solutions on such manifolds.http://www.sciencedirect.com/science/article/pii/S0370269323001363 |
| spellingShingle | Bob Holdom Cosmologies with turning points Physics Letters B |
| title | Cosmologies with turning points |
| title_full | Cosmologies with turning points |
| title_fullStr | Cosmologies with turning points |
| title_full_unstemmed | Cosmologies with turning points |
| title_short | Cosmologies with turning points |
| title_sort | cosmologies with turning points |
| url | http://www.sciencedirect.com/science/article/pii/S0370269323001363 |
| work_keys_str_mv | AT bobholdom cosmologieswithturningpoints |