Transmission through a quantum dot in an Aharonov-Bohm ring

Motivated by a recent experiment by Yacoby et al. [Phys. Rev. Lett. 74, 4047 (1995)]. we calculate the transmission through a quantum dot which is embedded in one arm of an Aharonov-Bohm (AB) ring. We allow for several channels in the AB ring. The electron-electron interaction within the dot is treated in a self-consistent mean-field approximation. We show that the amplitude of the Phi(0)-periodic Aharonov-Bohm oscillations generically vanishes close to a conductance resonance of the dot. This leads to a sudden phase change by pi in these oscillations, in agreement with observation.