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, th e electron interacts with a single magnetic impurity via an exchange coupli ng. The impurity can cause a spin-flip scattering leading to reduction of t he amplitude of Aharonov-Bohm oscillations. Here decoherence occurs in spit e of the absence of inelastic scattering. Its origin is traced to the inter action induced entanglement of quantum states. (C) 2001 Elsevier Science Lt d. All rights reserved.