Field theoretical study of disorder in non-Hermitian topological models

Non-Hermitian systems have provided a rich platform to study unconventional topological phases. These phases are usually robust against external perturbations that respect certain symmetries of the system. In this Letter, we provide a different method to analytically study the effect of disorder, using tools from quantum field theory applied to discrete models around the phase-transition points. We investigate two different one-dimensional models, the paradigmatic non-Hermitian Su-Schrieffer-Heeger model and an s-wave superconductor with imbalanced pairing. These analytic results are compared to numerical simulations in the discrete models. It is found that the systems are driven from a topological to a trivial phase in the same way.