Is chiral supersymmetry emanant or emergent?

Abstract

The extended Majorana Nicolai model is one of the simplest models of supersymmetry realized on a fermionic chain in $1+1$ dimensions. Within a certain parameter region, the extended theory breaks the supersymmetry spontaneously, but it has a distinguished feature that the general counting rule of the Nambu-Goldstone mode does not apply: we observe twice as many low-energy degrees of freedom than the broken lattice symmetry. We argue that the extra degrees of freedom originate from the spontaneous breaking of the emergent chiral supersymmetry. This chiral supersymmetry becomes an emanant symmetry in the non-interacting limit.