Anomalous localization and mobility edges in non-Hermitian quasicrystals with disordered imaginary gauge fields

How localization emerges in open wave systems can differ fundamentally from the familiar picture in closed materials. Here we show that a quasiperiodic chain with spatially disordered non-reciprocal couplings supports a form of localization in which the relevant boundary does not separate spreading and trapped waves, but two different kinds of confinement. One regime shows erratic skin accumulation at disorder-selected positions inside the lattice, whereas the other shows conventional Anderson localization with centers distributed across the system. Adding longer-range hopping turns this transition into an anomalous mobility edge between these two localized sectors. We identify the transition using real-space profiles, Lyapunov exponents, spectral winding, and wave-packet evolution. For individual disorder realizations, wave packets drift in a direction fixed by spectral topology, while averaging over disorder cancels opposite drifts and restores conventional transport. These results provide experimentally accessible signatures of anomalous localization in engineered open systems. The authors investigate localization in non-Hermitian quasicrystals with disordered imaginary gauge fields. They identify anomalous mobility edges separating erratic skin-localized and Anderson-localized states, revealed by spectra, topology and dynamics.