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

TL;DR

This paper investigates how boundaries in a (2+1)-dimensional Maxwell-Chern-Simons theory affect supersymmetry, revealing conditions for partial preservation and mechanisms for SUSY breaking including edge states and explicit action variation.

Contribution

It identifies boundary conditions that preserve partial supersymmetry and uncovers two distinct SUSY-breaking mechanisms in Maxwell-Chern-Simons theory with boundaries.

Findings

Partial  supersymmetry preserved under specific boundary conditions

Explicit SUSY breaking occurs when the action's SUSY variation does not vanish

Anomalous SUSY breaking due to unpaired fermionic edge states

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.