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Journal Article

#### Cosmology from Group Field Theory Formalism for Quantum Gravity

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##### Fulltext (public)

1303.3576v3.pdf

(Preprint), 142KB

PRL111_031301.pdf

(Any fulltext), 138KB

##### Supplementary Material (public)

There is no public supplementary material available

##### Citation

Gielen, S., Oriti, D., & Sindoni, L. (2013). Cosmology from Group Field Theory
Formalism for Quantum Gravity.* Physical Review Letters,* *111*:
031301. doi:10.1103/PhysRevLett.111.031301.

Cite as: http://hdl.handle.net/11858/00-001M-0000-000E-CA9F-5

##### 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.