- Letter
Non-Hermitian multipole skin effects challenge localization
Phys. Rev. B 113, L100203 – Published 24 March, 2026
DOI: https://doi.org/10.1103/c1jr-zqxg
Abstract
We study the effect of quenched disorder on the non-Hermitian skin effect in systems that conserve a U(1) charge and its associated multipole moments. In particular, we generalize the Hatano-Nelson argument for a localization transition in disordered, nonreciprocal systems to the interacting case. When only U(1) charge is conserved, we show that there is a transition between a skin-effect phase, in which charges cluster at a boundary, and a many-body localized phase, in which charges localize at random positions. In the dynamics of entanglement, this coincides with an area-to-volume-law transition. For systems without boundaries, the skin effect becomes a delocalized phase with a unidirectional current. If dipoles or higher multipoles are conserved, we show that the non-Hermitian skin effect remains stable to arbitrary disorder. Counterintuitively, the system is therefore always delocalized under periodic boundary conditions, regardless of disorder strength.