Mechanism of current noise spectrum in a nonequilibirum Kondo dot system

TL;DR

This paper investigates the nonequilibrium Kondo effects on quantum noise spectra in quantum dot systems, revealing characteristic features linked to Kondo oscillations and interference phenomena.

Contribution

It provides a systematic analysis of nonequilibrium Kondo mechanisms in current noise spectra using advanced dissipaton equations, highlighting new spectral features and interference effects.

Findings

Identification of nonequilibrium Kondo features in noise spectra within a[-eV, eV]

Observation of asymmetrical peaks at a=\u0000a a( ext{mu}_L- ext{mu}_R) in the noise spectrum

Detection of Kondo-Fano interference effects between resonance channels

Abstract

We systematically study the nonequilibirum Kondo mechanisms of quantum noise spectrum based on the accurate dissipaton--equation--of--motion evaluations. By comparing the noise spectra between the equilibrium and nonequilibrium cases and between the non-Kondo and Kondo regimes, we identify the nonequilibrium Kondo features in the current noise spectrum, appearing in the region of $\omega\in [-eV, eV]$. The Kondo characteristic at $\omega=\pm eV=\pm (\mu_{\rm L}-\mu_{\rm R})$ display asymmetrical upturns and remarkable peaks in $S(\omega)$ and $dS(\omega)/d\omega$, respectively. These features are originated from the Rabi interference of the transport current dynamics, with the Kondo oscillation frequency of $|eV|$. The minor but very distinguishable inflections, crossing over $\omega=-eV$ to $\omega=+eV$, would be related to a sort of Kondo-Fano interference between two Kondo resonances channels.