RG flows in super-renormalizable scalar field theories

Massless scalar field theories in d<4 suffer from IR divergences that hinder a direct perturbative approach. On the other hand, massive theories are well-defined and their critical regime can be recovered by Borel resumming the perturbative expansion. Within this approach, we show how the phase diagram of \phi^4 models in two and three dimensions depend exactly on a class of renormalization schemes. In particular, we show that the same renormalization scheme
can admit two equivalent descriptions, non-perturbatively related to each other (a sort of duality) and that fixed points can merge and move into the complex plane in complex conjugate pairs, making the phase transition no longer visible from a classically unbroken or broken phase.

Recording available at: https://mediaspace.epfl.ch/channel/High+Energy+Theory+Seminars/32518