Cosmological evolution as squeezing: a toy model for group field cosmology

Adjei, Eugene and 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

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Abstract

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.

Item Type: Article
Keywords: quantum cosmology, group field theory, squeezed states
Schools/Departments: University of Nottingham, UK > Faculty of Science > School of Mathematical Sciences
Identification Number: https://doi.org/10.1088/1361-6382/aaba11
Depositing User: Eprints, Support
Date Deposited: 08 Jun 2018 14:05
Last Modified: 08 Jun 2018 14:09
URI: http://eprints.nottingham.ac.uk/id/eprint/52323

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