Singularities in loop quantum cosmology
Fuente:
arXiv
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| Autori principali: | , , |
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| Natura: | Preprint |
| Pubblicazione: |
2025
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| _version_ | 1866913068398673920 |
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| author | Bojowald, Martin Diaz, Manuel Duque, Erick I. |
| author_facet | Bojowald, Martin Diaz, Manuel Duque, Erick I. |
| contents | Quantum effects are expected to modify the cosmological dynamics of the early universe while maintaining some (potentially discrete) notion of space-time structure. In one approach, loop quantum cosmology, current models are shown here to either be incompatible with a consistent space-time structure, or to have physical singularities. The latter happens in spite of a non-zero scale factor in the isotropic background dynamics. A new effective Friedmann equation shows that a bounce is obtained at sub-Planckian densities, preceded by a physical singularity at infinite scale factor that resembles a time-reversed big rip. The entire phase is accompanied by rapid changes of the Hubble radius. In addition, a new version of perturbative inhomogeneity in loop quantum cosmology is introduced that maintains a consistent space-time structure and has a non-singular background dynamics. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2507_08116 |
| institution | arXiv |
| publishDate | 2025 |
| record_format | arxiv |
| spellingShingle | Singularities in loop quantum cosmology Bojowald, Martin Diaz, Manuel Duque, Erick I. General Relativity and Quantum Cosmology Cosmology and Nongalactic Astrophysics Quantum effects are expected to modify the cosmological dynamics of the early universe while maintaining some (potentially discrete) notion of space-time structure. In one approach, loop quantum cosmology, current models are shown here to either be incompatible with a consistent space-time structure, or to have physical singularities. The latter happens in spite of a non-zero scale factor in the isotropic background dynamics. A new effective Friedmann equation shows that a bounce is obtained at sub-Planckian densities, preceded by a physical singularity at infinite scale factor that resembles a time-reversed big rip. The entire phase is accompanied by rapid changes of the Hubble radius. In addition, a new version of perturbative inhomogeneity in loop quantum cosmology is introduced that maintains a consistent space-time structure and has a non-singular background dynamics. |
| title | Singularities in loop quantum cosmology |
| topic | General Relativity and Quantum Cosmology Cosmology and Nongalactic Astrophysics |
| url | https://arxiv.org/abs/2507.08116 |