Cosmology from Group Field Theory Formalism for Quantum Gravity
Abstract
We identify a class of condensate states in the group field theory (GFT) approach to quantum gravity that can be interpreted as macroscopic homogeneous spatial geometries. We then extract the dynamics of such condensate states directly from the fundamental quantum GFT dynamics, following the procedure used in ordinary quantum fluids. The effective dynamics is a non-linear and non-local extension of quantum cosmology. We also show that any GFT model with a kinetic term of Laplacian type gives rise, in a semi-classical (WKB) approximation and in the isotropic case, to a modified Friedmann equation. This is the first concrete, general procedure for extracting an effective cosmological dynamics directly from a fundamental theory of quantum geometry.
Cite
@article{arxiv.1303.3576,
title = {Cosmology from Group Field Theory Formalism for Quantum Gravity},
author = {Steffen Gielen and Daniele Oriti and Lorenzo Sindoni},
journal= {arXiv preprint arXiv:1303.3576},
year = {2013}
}
Comments
4 pages, revtex, APS style; v2: minor changes, notation around eq.(23) corrected; v3: shortened version to appear in PRL, with minor changes in the text and a new title, but no changes in content