Alicia Castro: Characterization of gravitational universality classes for order-4 random tensor models

mercredi 25 mars 2026, 14:00 → 15:00 Europe/Paris

Random tensor models can be used as combinatorial devices to generate
Euclidean dynamical triangulations. A physical continuum limit of
dynamical triangulations requires a suitable generalization of the
double-scaling limit of random matrices. This limit corresponds to a
fixed point of a pregeometric Renormalization Group flow in which the
tensor size N serves as the Renormalization Group scale. We search for
corresponding fixed points in order-4 random tensor models associated to
dynamical triangulations in 4 dimensions. In a O(N)^4 symmetric setting,
we discuss the resulting phase portrait as a function of the regulator
parameters. We optimize our results, identifying parameter values for
which the results are minimally sensitive to parameter changes. We find
three fixed-point candidates: only one of them is real across the entire
parameter range, but only has two relevant directions. This should be
contrasted with the university class of the Reuter fixed point in
continuum quantum gravity, very likely characterized by three relevant
directions. We conclude that simple combinatorial models of Euclidean
triangulations and the Reuter fixed point most likely lie in different
universality classes. This talk is based on: 2602.09257