Title: Counting Tensor Invariants with Defect TQFT 

Abstract: A tensor transforming under a unitary-orthogonal symmetry group carries finitely many invariant observables of each degree. Counting these so-called tensor invariants is an important problem in the theory of tensor models, and it reduces to counting tuples of permutations modulo a conjugation action.

In this talk, I will explain how this counting can be interpreted as the partition function of an untwisted Dijkgraaf-Witten topological quantum field theory with defects. The permutations groups appearing in the tensor invariant counting problem are exactly the defect data of a stratified manifold, and the tensor invariant is then the groupoid cardinality of the associated gauge groupoid. I conclude with physics applications coming from this perspective of tensor invariants.
 

This talk is based on forthcoming joint work with Remi Cocou Avhou, Noan Botcazou-Brasse, and Reiko Toriumi. 
 

Speaker: Michael Lathwood (OIST)

This talk will also be broadcast online via Zoom: 
Meeting ID: 974 4775 6289
Passcode: 371131

Language: English

This lecture is part of the  Thematic Program on “New Frontiers in Gauge Theory, Topology, and Physics” (TP26GT).