No Ward-Takahashi identity violation for Abelian tensorial group field theories with a closure constraint

This paper aims at investigating the nonperturbative functional renormalization group for tensorial group field theories with nontrivial kinetic action and closure constraint. We consider the quartic melonic justrenormalizable [U(1)](6) model and show that due to this closure constraint the first order Ward-Takahashi identity takes the trivial form as for the models with propagators proportional to identity. We then construct the new version of the effective vertex expansion applicable to this class of models, which in particular allows us to close the hierarchical structure of the flow equations in the melonic sector. As a consequence, there are no additional constraints on the flow equations, and then we can focus on the existence of the physical Wilson-Fisher fixed-points in the symmetric phase.

Automated summary

This paper investigates the nonperturbative functional renormalization group for tensorial group field theories with nontrivial kinetic action and closure constraint, focusing on the quartic melonic justrenormalizable [U(1)](6) model. The first order Ward-Takahashi identity takes a trivial form due to the closure constraint, and a new version of effective vertex expansion is constructed for this class of models, allowing closure of the hierarchical structure of the flow equations in the melonic sector. The existence of physical Wilson-Fisher fixed-points in the symmetric phase is then a key focus of the study.