Time evolution of semiclassical states in the one-vertex model of quantum-reduced loop gravity
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arXiv
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| Format: | Preprint |
| Veröffentlicht: |
2026
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| _version_ | 1866917377791229952 |
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| author | Mäkinen, Ilkka |
| author_facet | Mäkinen, Ilkka |
| contents | We compute numerically the time evolution of simple semiclassical states describing homogeneous and isotropic spatial geometries in quantum-reduced loop gravity under a deparametrized formulation of the dynamics, in which a reference matter field is taken as a relational time variable for the dynamics of quantum states of the gravitational field. The states which we consider are defined on the Hilbert space of a spin network graph formed by a single six-valent vertex. We find that the quantum dynamics is generally in close agreement with the semiclassical effective dynamics of a homogeneous and isotropic universe throughout the range of validity of the numerical approximation. In particular, an initial state describing a contracting geometry undergoes a dynamical "bounce", where the contraction is halted and turned into an expansion by the quantum dynamics. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2604_00999 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | Time evolution of semiclassical states in the one-vertex model of quantum-reduced loop gravity Mäkinen, Ilkka General Relativity and Quantum Cosmology We compute numerically the time evolution of simple semiclassical states describing homogeneous and isotropic spatial geometries in quantum-reduced loop gravity under a deparametrized formulation of the dynamics, in which a reference matter field is taken as a relational time variable for the dynamics of quantum states of the gravitational field. The states which we consider are defined on the Hilbert space of a spin network graph formed by a single six-valent vertex. We find that the quantum dynamics is generally in close agreement with the semiclassical effective dynamics of a homogeneous and isotropic universe throughout the range of validity of the numerical approximation. In particular, an initial state describing a contracting geometry undergoes a dynamical "bounce", where the contraction is halted and turned into an expansion by the quantum dynamics. |
| title | Time evolution of semiclassical states in the one-vertex model of quantum-reduced loop gravity |
| topic | General Relativity and Quantum Cosmology |
| url | https://arxiv.org/abs/2604.00999 |