Nonequilibirum noise spectrum and Coulomb-blockade-assisted Rabi interference in a double-dot Aharonov-Bohm interferometer

TL;DR

This paper explores nonequilibrium charge coherence and noise spectra in a double-dot Aharonov-Bohm interferometer, revealing Coulomb-blockade-assisted Rabi interference and its sensitivity to magnetic flux, using advanced dynamical methods.

Contribution

It introduces the concept of Coulomb-blockade-assisted Rabi interference in a double-dot AB interferometer and analyzes its spectroscopic signatures and dynamics.

Findings

Spectral peaks and dips from Rabi oscillations linked to environment-assisted tunneling.

Total circuit noise spectrum shows complex interplay of mechanisms.

Coulomb-blockade-assisted Rabi interference has distinct signatures in noise spectra.

Abstract

We investigate the charge-states coherence underlying the nonequilibirum transport through a spinless double-dot Aharonov-Bohm (AB) interferometer. Both the current noise spectrum and real-time dynamics are evaluated with the well-established dissipaton-equation-of-motion method. The resulted spectrums show the characteristic peaks and dips, arising from coherent Rabi oscillation dynamics, with the environment-assisted indirect inter-dot tunnel coupling mechanism. The observed spectroscopic features are in a quantitative agreement to the real-time dynamics of the reduced density matrix off-diagonal element between two charge states. As the aforementioned mechanism, these characteristics of coherence are very sensitive to the AB phase. While this is generally true for cross-correlation spectrum, the total circuit noise spectrum that is experimentally more accessible shows remarkably rich interplay between various mechanisms. The most important finding of this work is the existence of Coulomb-blockade-assisted Rabi interference, with very distinct signatures arising from the interplay between the AB interferometer and the interdot Coulomb interaction induced Fano resonance.