Mechanism of current noise spectrum in a nonequilibirum Kondo dot system

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 $\omega=\pm eV=\pm (\mu_{\rm L}-\mu_{\rm R})$displayasymmetricalupturnsandremarkablepeaksin$S(\omega)$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 $\mathrm{\mid }eV\mathrm{\mid }$. 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.