Reentrant Non-Hermitian Skin Effect Induced by Correlated Disorder

Abstract: The interplay of non-Hermiticity and disorder drastically influences the system's localization properties, giving rise to intriguing quantum phenomena. Although the intrinsic non-Hermitian skin effect (NHSE) is robust against weak disorder even in a one-dimensional system, it becomes Anderson localization under strong disorder. Here, we study an Anderson localization-delocalization transition by coupling a strongly disordered Hatano-Nelson (HN) chain to a disordered Hermitian chain with their disorders anti-symmetrically correlated with each other. Regardless of the disorder strength, as the inter-chain coupling strength increases, an Anderson delocalization can occur. This leads to a reentrant NHSE due to the interplay of nonreciprocal hopping and correlated disorder. Furthermore, the Anderson localization-delocalization transition is well captured by the real-space winding number. This reentrant NHSE, under anti-symmetric disorder, is a remarkably nontrivial physical phenomenon without a Hermitian counterpart. We then experimentally test this phenomenology by implementing our model in electrical circuits, and observe the reentrant NHSE by measuring the voltage response.