Experimental Observation of Erratic Non-Hermitian Skin Effect in Phononic Crystals
Phys. Rev. Lett. 137, 186602 – Published 30 October, 2026
DOI: https://doi.org/10.1103/yfc3-ny3b
Abstract
The erratic non-Hermitian skin effect (ENHSE), emerging from the interplay between disorder and locally nonreciprocal yet globally reciprocal couplings, has reshaped the conventional bulk-boundary correspondence through its disorder-dependent localization properties. Here, we experimentally observe the localization characteristics of the ENHSE in a one-dimensional phononic crystal composed of 20 coupled acoustic resonators. In the experiment, the disordered imaginary gauge fields are implemented through actively controlled nonreciprocal couplings. The results show that the erratic localization occurs in the bulk independently of the excitation position, with the main and satellite peaks precisely located at the local maxima of the cumulative gauge field, in accordance with random-walk extreme-value statistics. Remarkably, the selective manipulation of satellite peaks can be realized by tuning the staggered disorder strengths in a dimerized chain. These findings deepen the understanding of non-Hermitian physics and establish a new route for disorder-engineered non-Hermitian wave control.
