Double scaling limit for the $O(N)^3$-invariant tensor model

TL;DR

This paper analyzes the double scaling limit of the $O(N)^3$-invariant tensor model, revealing a summable limit that incorporates contributions from all orders in the $1/N$ expansion through combinatorial and diagrammatic methods.

Contribution

It introduces a novel double scaling limit for the tensor model that sums over all orders in the $1/N$ expansion, using combinatorial analysis of Feynman graphs.

Findings

Double scaling limit incorporates all orders in $1/N$ expansion.

The limit is summable, unlike in matrix models.

Graph singularities are characterized at each order.

Abstract

We study the double scaling limit of the $O(N)^3$-invariant tensor model, initially introduced in Carrozza and Tanasa, Lett. Math. Phys. (2016). This model has an interacting part containing two types of quartic invariants, the tetrahedric and the pillow one. For the 2-point function, we rewrite the sum over Feynman graphs at each order in the $1/N$ expansion as a \emph{finite} sum, where the summand is a function of the generating series of melons and chains (a.k.a. ladders). The graphs which are the most singular in the continuum limit are characterized at each order in the $1/N$ expansion. This leads to a double scaling limit which picks up contributions from all orders in the $1/N$ expansion. In contrast with matrix models, but similarly to previous double scaling limits in tensor models, this double scaling limit is summable. The tools used in order to prove our results are combinatorial, namely a thorough diagrammatic analysis of Feynman graphs, as well as an analysis of the singularities of the relevant generating series.