Anomalous hybridization of spectral winding topology in quantized steady-state responses

Abstract

Quantized response is one distinguishing feature of a topological system. In non-Hermitian systems, the spectral winding topology yields quantized steady-state response. By considering two weakly coupled non-Hermitian chains, we discover that the spectral winding topology of one chain can be probed by a steady-state response defined solely on the other chain, even when other important properties, e.g., {energetics} and entanglement entropy, indicate that eigen-solutions are effectively {not hybridized} between the two chains. This intriguing phenomenon, as carefully investigated in a large parameter space with a varying system size, not only offers a new angle to understand interchain signal propagation in a non-Hermitian setting but also reveals unexpected physics of spectral winding topology vs quantized response.