2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/215833We propose a scheme utilising a quantum interference phenomenon to switch the transport of atoms in a 1D optical lattice through a site containing an impurity atom. The impurity represents a qubit which in one spin state is transparent to the probe atoms, but in the other acts as a single atom mirror. This allows a single-shot quantum non-demolition measurement of the qubit spin.RevTeX 4, 5 Figures, 4 PagesQuantum PhysicsSoft Condensed Mattertext