Entanglement induced decoherence of Aharonov–Bohm oscillations in mesoscopic rings

We study a simple model of decoherence of Aharonov–Bohm oscillations in the transmission across a metallic mesoscopic ring. In one arm of the ring, the electron interacts with a single magnetic impurity via an exchange coupling. The impurity can cause a spin-flip scattering leading to reduction of the amplitude of Aharonov–Bohm oscillations. Here decoherence occurs in spite of the absence of inelastic scattering. Its origin is traced to the interaction induced entanglement of quantum states.