title: Kondo correlations and the Fano effect in closed Aharonov-Bohm interferometers.
abstract: We study the Fano-Kondo effect in a closed Aharonov-Bohm (AB) interferometer which contains a single-level quantum dot and predict a frequency doubling of the AB oscillations as a signature of Kondo-correlated states. Using the Keldysh formalism, the Friedel sum rule, and the numerical renormalization group, we calculate the exact zero-temperature linear conductance G as a function of the AB phase phi and level position epsilon. In the unitary limit, G(phi) reaches its maximum 2e(2)/h at phi = pi/2. We find a Fano-suppressed Kondo plateau for G(epsilon) similar to recent experiments.
authors.affiliation: Theoretische Physik III, Elektronische Korrelationen und Magnetismus, Universität Augsburg, D-86135 Augsburg, Germany.
authors.forename: W
authors.initials: W
authors.lastname: Hofstetter
authors.forename: J
authors.initials: J
authors.lastname: König
authors.forename: H
authors.initials: H
authors.lastname: Schoeller