Stable Interacting (2 + 1)d Conformal Field Theories at the Boundary of a class of (3 + 1)d Symmetry Protected Topological Phases

Zhen Bi, Alex Rasmussen, Yoni BenTov +1

Motivated by recent studies of symmetry protected topological (SPT) phases, we explore the possible gapless quantum disordered phases in the $(2+1)d$ nonlinear sigma model defined…