Non-Hermitian generalizations of the Yao-Lee model augmented by SO(3)-symmetry-breaking terms

Abstract

We investigate non-Hermitian versions of the Yao-Lee model, supplemented by various kinds of SO(3)-symmetry-breaking terms, preserving the solvability of the model. The parent model hosts three species of Majorana fermions, thereby serving as an extension of the two-dimensional Kitaev model on the honeycomb lattice. The non-Hermitian couplings represent generic situations when the system is coupled to the environment and, thus, undergoes dissipation. The resulting eigenvalue spectrum and the eigenmodes show a rich structure of exceptional points as well as non-Hermitian skin effects. We chart out such exotic behaviour for some representative parameter regimes.