Entanglement-induced electron coherence in a mesoscopic ring with two magnetic impurities

We investigate the Aharonov-Bohm (AB) interference pattern in the electron transmission througha mesoscopic ring in which two identical non-interacting magnetic impurities are embedded. Adoptinga quantum waveguide theory, we derive the exact transmission probability amplitudes and studythe influence of maximally entangled states of the impurity spins on the electron transmittivity interferencepattern. For suitable electron wave vectors, we show that the amplitude of AB oscillationsin the absence of impurities is in fact not reduced within a wide range of the electron-impurity couplingconstant when the maximally entangled singlet state is prepared. Such state is thus able toinhibit the usual electron decoherence due to scattering by magnetic impurities. We also show howthis maximally entangled state of the impurity spins can be generated via electron scattering.