Detecting entanglement with transport measurement in weakly interacting and fluctuating systems
Phys. Rev. B 113, 035447 – Published 30 January, 2026
DOI: https://doi.org/10.1103/77cs-7k18
Abstract
Measuring entanglement entropy in interacting, multipartite systems remains a significant experimental challenge. We address this challenge by developing a protocol to measure von Neumann entropy (VNE) and mutual information in quantum transport systems with both many-body interactions and multiple subsystems. Our analysis indicates that the vital connection between VNE and two-point correlation functions persists under these realistic conditions. We provide detailed derivations showing that this relation holds for weakly interacting systems via perturbation theory and for systems near a stable saddle point via the Hubbard-Stratonovich transformation. The measurement is shown to be feasible for systems with boundary interactions and, critically, for bulk-interacting systems subject to a quantum quench of their internal couplings. Our work provides a pathway to experimentally quantify entanglement in complex interacting systems and establishes mutual information as an experimentally accessible indicator for system-environment entanglement.
