Speaker
Description
Symmetric mass generation denotes an unconventional continuum QFT mechanism, in which fermions acquire mass without a fermion bilinear condensate, i.e., without spontaneous symmetry breaking. The symmetric mass generation (SMG) mechanism can be studied in a Euclidean lattice model with two flavors of massless staggered fermions and two independent four-fermion interactions. In this talk, I will present the latest results for this model, reported in https://arxiv.org/abs/2512.24836 and https://arxiv.org/abs/2602.18360, obtained with the fermion bag Monte Carlo method on large three-dimensional lattices. We find evidence for conventional second-order critical points separating the massless fermion and broken phases, as well as the broken and SMG phases. The former transition is of the Gross-Neveu type, appearing, e. g., in twisted bilayer graphene, and the latter belongs to the 3D–XY universality class. Surprisingly, the two critical points appear to merge at a multicritical point with enhanced symmetry, which may explain the recently discovered second-order transition between the massless fermion and the SMG phase.