Group field theories generating polyhedral complexes

TL;DR

This paper introduces two new classes of group field theories that generate polyhedral complexes, expanding their capacity to encompass the full state space of loop quantum gravity and potentially aiding in renormalization studies.

Contribution

It presents novel group field theories that generate polyhedral complexes and cover the entire loop quantum gravity state space, including multiple valencies and dual weighting techniques.

Findings

New group field theories generate polyhedral complexes.

The theories encompass the full loop quantum gravity state space.

Potential applications in renormalizability studies.

Abstract

Group field theories are a generalization of matrix models which provide both a second quantized reformulation of loop quantum gravity as well as generating functions for spin foam models. While states in canonical loop quantum gravity, in the traditional continuum setting, are based on graphs with vertices of arbitrary valence, group field theories have been defined so far in a simplicial setting such that states have support only on graphs of fixed valency. This has led to the question whether group field theory can indeed cover the whole state space of loop quantum gravity. In this contribution based on [1] I present two new classes of group field theories which satisfy this objective: i) a straightforward, but rather formal generalization to multiple fields, one for each valency and ii) a simplicial group field theory which effectively covers the larger state space through a dual weighting, a technique common in matrix and tensor models. To this end I will further discuss in some detail the combinatorial structure of the complexes generated by the group field theory partition function. The new group field theories do not only strengthen the links between the mentioned quantum gravity approaches but, broadening the theory space of group field theories, they might also prove useful in the investigation of renormalizability.