Interacting topological phases and modular invariance
Interacting topological phases and modular invariance
We discuss (2+1)-dimensional topological superconductors with ${N}_{f}$ left- and right-moving Majorana edge modes and a ${\mathbb{Z}}_{2}\ifmmode\times\else\texttimes\fi{}{\mathbb{Z}}_{2}$ symmetry. In the absence of interactions, these phases are distinguished by an integral topological invariant ${N}_{f}$. With interactions, the edge state in the case of ${N}_{f}=8$ is unstable against interactions, and a ${\mathbb{Z}}_{2}\ifmmode\times\else\texttimes\fi{}{\mathbb{Z}}_{2}$ invariant …