Bilocal effective action for tensor models
Abstract:
Motivated by the central role that a bilocal action formulation plays for
the SYK model and its holographic interpretation, I will introduce the
two-particle-irreducible effective action for tensor models, and
show that it plays a similar role. In particular, I will show that it
allows to derive an effective action for the soft modes governing the
spontaneous and explicit breaking of time reparametrization invariance
(the Schwarzian action, as in SYK), and of the global symmetry group of
the tensor model (a non-linear sigma model action). Furthermore, time
permitting, I will discuss the 1/N expansion of the Gurau-Witten model up
to fourth order, and its interpretation as the one-loop approximation for
an auxiliary bilocal theory.