Generalised Gaussian states in group field theory

Author:

Andrea Calcinari, Steffen Gielen

Keyword:

General Relativity and Quantum Cosmology, General Relativity and Quantum Cosmology (gr-qc), High Energy Physics - Theory (hep-th)

journal:

date:

2023-10-11 16:00:00

Abstract

We define generalised Gaussian states in group field theory built on a single field mode, and study their semiclassical properties relevant for the application to cosmology. These states are generalisations of coherent, squeezed and thermal states considered previously. As two possible characterisations of semiclassicality, we contrast the requirement of small relative fluctuations in volume and energy with the saturation of the Robertson-Schr\"odinger uncertainty principle. We find that for the most general class of states the appearance of small relative fluctuations, which we take as the main criterion relevant for the emergence of cosmology, is mostly determined by the amount of displacement used to define the state. We also observe that defining such generalised Gaussian states is less straightforward in the algebraic approach to canonical quantisation of GFT, and discuss special cases.

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