Experimental observation of genuine quantum probability backflow

Establish an unambiguous experimental observation of genuine quantum probability backflow in a physical system.

Background

Quantum probability backflow is the occurrence of locally negative probability current despite a state containing only positive-momentum components. Although theoretical studies and classical-wave analogues have advanced substantially, the paper identifies the lack of an unambiguous experimental observation of genuine quantum probability backflow as an unresolved challenge.

The paper develops a theoretical proposal for magnetic-field-controlled backflow in Landau systems, including Schrödinger and Pauli descriptions, but it does not perform an experimental observation. Consequently, realizing and unambiguously verifying genuine quantum backflow remains an open problem beyond the results established here.