Cosmological evolution as squeezing: a toy model for group field cosmology
We present a simple model of quantum cosmology based on the group field theory (GFT) approach to quantum gravity. The model is formulated on a subspace of the GFT Fock space for the quanta of geometry, with a fixed volume per quantum. In this Hilbert space, cosmological expansion corresponds to the...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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IOP Publishing
2018
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| Online Access: | https://eprints.nottingham.ac.uk/52323/ |
| _version_ | 1848798700292276224 |
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| author | Adjei, Eugene Gielen, Steffen Wieland, Wolfgang |
| author_facet | Adjei, Eugene Gielen, Steffen Wieland, Wolfgang |
| author_sort | Adjei, Eugene |
| building | Nottingham Research Data Repository |
| collection | Online Access |
| description | We present a simple model of quantum cosmology based on the group field theory (GFT) approach to quantum gravity. The model is formulated on a subspace of the GFT Fock space for the quanta of geometry, with a fixed volume per quantum. In this Hilbert space, cosmological expansion corresponds to the generation of new quanta. Our main insight is that the evolution of a flat Friedmann–Lemaître–Robertson–Walker universe with a massless scalar field can be described on this Hilbert space as squeezing, familiar from quantum optics. As in GFT cosmology, we find that the three-volume satisfies an effective Friedmann equation similar to the one of loop quantum cosmology, connecting the classical contracting and expanding solutions by a quantum bounce. The only free parameter in the model is identified with Newton’s constant. We also comment on the possible topological interpretation of our squeezed states. This paper can serve as an introduction into the main ideas of GFT cosmology without requiring the full GFT formalism; our results can also motivate new developments in GFT and its cosmological application. |
| first_indexed | 2025-11-14T20:23:56Z |
| format | Article |
| id | nottingham-52323 |
| institution | University of Nottingham Malaysia Campus |
| institution_category | Local University |
| language | English |
| last_indexed | 2025-11-14T20:23:56Z |
| publishDate | 2018 |
| publisher | IOP Publishing |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | nottingham-523232018-06-08T14:09:54Z https://eprints.nottingham.ac.uk/52323/ Cosmological evolution as squeezing: a toy model for group field cosmology Adjei, Eugene Gielen, Steffen Wieland, Wolfgang We present a simple model of quantum cosmology based on the group field theory (GFT) approach to quantum gravity. The model is formulated on a subspace of the GFT Fock space for the quanta of geometry, with a fixed volume per quantum. In this Hilbert space, cosmological expansion corresponds to the generation of new quanta. Our main insight is that the evolution of a flat Friedmann–Lemaître–Robertson–Walker universe with a massless scalar field can be described on this Hilbert space as squeezing, familiar from quantum optics. As in GFT cosmology, we find that the three-volume satisfies an effective Friedmann equation similar to the one of loop quantum cosmology, connecting the classical contracting and expanding solutions by a quantum bounce. The only free parameter in the model is identified with Newton’s constant. We also comment on the possible topological interpretation of our squeezed states. This paper can serve as an introduction into the main ideas of GFT cosmology without requiring the full GFT formalism; our results can also motivate new developments in GFT and its cosmological application. IOP Publishing 2018-04-16 Article PeerReviewed application/pdf en cc_by https://eprints.nottingham.ac.uk/52323/1/Adjei_2018_Class._Quantum_Grav._35_105016.pdf Adjei, Eugene, Gielen, Steffen and Wieland, Wolfgang (2018) Cosmological evolution as squeezing: a toy model for group field cosmology. Classical and Quantum Gravity, 35 (10). 105016/1-105016/18. ISSN 1361-6382 quantum cosmology group field theory squeezed states http://iopscience.iop.org/article/10.1088/1361-6382/aaba11 doi:10.1088/1361-6382/aaba11 doi:10.1088/1361-6382/aaba11 |
| spellingShingle | quantum cosmology group field theory squeezed states Adjei, Eugene Gielen, Steffen Wieland, Wolfgang Cosmological evolution as squeezing: a toy model for group field cosmology |
| title | Cosmological evolution as squeezing: a toy model for group field cosmology |
| title_full | Cosmological evolution as squeezing: a toy model for group field cosmology |
| title_fullStr | Cosmological evolution as squeezing: a toy model for group field cosmology |
| title_full_unstemmed | Cosmological evolution as squeezing: a toy model for group field cosmology |
| title_short | Cosmological evolution as squeezing: a toy model for group field cosmology |
| title_sort | cosmological evolution as squeezing: a toy model for group field cosmology |
| topic | quantum cosmology group field theory squeezed states |
| url | https://eprints.nottingham.ac.uk/52323/ https://eprints.nottingham.ac.uk/52323/ https://eprints.nottingham.ac.uk/52323/ |