Field Theoretical Study of Disorder in Non-Hermitian Topological Models

Abstract

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 work, we provide a new method to analytically study the effect of disorder, using tools from quantum field theory applied to discrete models around phase-transition points. We investigate two different one-dimensional models, the paradigmatic non-Hermitian SSH model and a s-wave superconductor with imbalanced pairing. These analytic results are compared to numerical simulations in the discrete models. An universal behavior is found for the two investigated models, namely that the systems are driven from a topological to a trivial phase for disorder strengths equal to about four times the energy scale of the model.