Extended Landauer-Büttiker Formula for Current through Open Quantum Systems with Gain or Loss
Phys. Rev. Lett. 136, 056304 – Published 4 February, 2026
DOI: https://doi.org/10.1103/trty-58r2
Abstract
The Landauer-Büttiker formula, which characterizes current through a finite region connected to leads, is a cornerstone in studying transport phenomena. We extend this formula using the Lindblad-Keldysh formalism to describe particle and energy currents in regions with gain or loss. The derived formula shows that gain or loss plays a notable role in shaping the transport properties. Based on this formula, we find that inversion symmetry breaking in the gain and loss terms or in the system can generate current, along with the anomalous phenomenon where disorder induces current. We also reveal how gain and loss affect thermal and electrical conductances, as well as the impact of bond loss-induced non-Hermitian skin effect on current. This Letter deepens and extends our understanding of transport phenomena in open systems.
