Noise of Kondo dot with ac gate: Floquet-Green's function and Noncrossing Approximation Approach

TL;DR

This paper investigates how an ac gate affects the transport and noise properties of a Kondo quantum dot, revealing the robustness of the Kondo peak under weak modulation and its suppression under strong fields, with implications for distinguishing transport mechanisms.

Contribution

It introduces a Floquet-Green's function approach combined with the noncrossing approximation to analyze ac-driven Kondo quantum dots, highlighting the behavior of the Kondo peak and photon-assisted noise.

Findings

Kondo peak remains robust under weak ac modulation.

Strong ac fields significantly suppress the Kondo peak.

Photon-assisted noise lacks singularities, differentiating between noninteracting and Kondo resonances.

Abstract

The transport properties of an ac-driving quantum dot in the Kondo regime are studied by the Floquet-Green's function method with slave-boson infinite-$U$ noncrossing approximation. Our results show that the Kondo peak of the local density of states is robust against weak ac gate modulation. Significant suppression of the Kondo peak can be observed when the ac gate field becomes strong. The photon-assisted noise of Kondo resonance as a function of dc voltage does not show singularities which are expected for noninteracting resonant quantum dot. These findings suggest that one may make use of the photon-assisted noise measurement to tell apart whether the resonant transport is via noninteracting resonance or strongly-correlated Kondo resonance.