Finite-frequency current (shot) noise in coherent resonant tunneling through a coupled-quantum-dot interferometer

We examine the shot noise spectrum properties of coherent resonant tunneling in coupled quantum dots (CQDs) in both series and parallel arrangements by means of quantum rate equations and MacDonald's formula. Our results show that for a series-CQD with a relatively high dot-dot hopping Omega and Omega/Gamma greater than or similar to 1 (Gamma denotes the dot-lead tunnel-coupling strength), the noise spectrum exhibits a dip at the Rabi frequency 2 Omega in the case of noninteracting electrons, but the dip is supplanted by a peak in the case of strong Coulomb repulsion; furthermore, it becomes a dip again for a completely symmetric parallel-CQD by tuning the enclosed magnetic flux. (C) 2008 American Institute of Physics.