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

TL;DR

This paper investigates the shot noise spectrum in coherent resonant tunneling through coupled quantum dots, revealing how Coulomb interactions and magnetic flux influence the spectral features like dips and peaks.

Contribution

It provides a detailed analysis of the shot noise spectrum in coupled quantum dots, highlighting the effects of Coulomb repulsion and magnetic flux on spectral features.

Findings

Noise spectrum shows a dip at Rabi frequency for noninteracting electrons in series-CQD.

Strong Coulomb repulsion turns the dip into a peak.

Magnetic flux tuning can restore the dip in parallel-CQD.

Abstract

We examine the shot noise spectrum properties of coherent resonant tunneling in coupled quantum dots 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 $\Omega$, $\Omega/\Gamma\gtrsim 1$ ($\Gamma$ 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 enclosed magnetic-flux.