Edge states and anomalous SUSY in (2+1)-dimensional Maxwell Chern-Simons theory

Abstract: In a $(2+1)$-dimensional Maxwell-Chern-Simons theory coupled with a fermion and a scalar, which has $\mathcal{N}=2$ SUSY in absence of the boundary, the insertion of a spatial boundary breaks the supersymmetry. We show that only a subset of the boundary conditions allowed by the self-adjointness of the Hamiltonian can preserve partial $\mathcal{N}=1$ supersymmetry, while for the remaining boundary conditions SUSY is completely broken. In the latter case, we demonstrate two distinct SUSY-breaking mechanisms. For some of the SUSY-breaking boundary conditions, the SUSY variation of the action does not vanish which explicitly breaks SUSY. While for certain other boundary conditions, despite the invariance of action under SUSY transformations, unpaired fermionic edge states in the domain of the Hamiltonian leads to an anomalous breaking of the supersymmetry.