Melonic phase transition in group field theory


Group field theories have recently been shown to admit a 1/N expansion dominated by so-called “melonic graphs”’, dual to triangulated spheres. In this note, we deepen the analysis of this melonic sector. We obtain a combinatorial formula for the melonic amplitudes in terms of a graph polynomial related to a higher dimensional generalization of the Kirchhoff tree-matrix theorem. Simple bounds on these amplitudes show the existence of a phase transition driven by melonic interaction processes. We restrict our study to the Boulatov-Ooguri models, which describe topological BF theories and are the basis for the construction of four dimensional models of quantum gravity.

Letters in Mathematical Physics 104 8, 1003-1017
Aristide Baratin
Aristide Baratin
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