Full counting statistics of Kondo-type tunneling in a quantum dot: the fluctuation effect of Slave-Boson field

TL;DR

This paper investigates the full counting statistics of electron tunneling in a Kondo regime quantum dot using slave-boson mean field theory, revealing how Bose field fluctuations influence shot noise and current correlations.

Contribution

It introduces a self-consistent approach to include Bose field fluctuations in FCS calculations for Kondo quantum dots, highlighting their impact on noise characteristics.

Findings

Bose field fluctuations contribute to shot noise enhancement.

Particle number fluctuations significantly affect current correlations.

The method provides explicit expressions for counting field-dependent quantities.

Abstract

We study the full counting statistics (FCS) of electron tunneling through a multi-terminal quantum dot in the Kondo regime within the slave-boson mean field theory. By employing the A.O. Gogolin and A. Komnik's method of calculating the FCS generating function based on the nonequilibrium Green's function [Phys. Rev. B {\bf 73}, 195301 (2006)], we obtain the counting field $\lambda$-dependent self-consistent equations for the mean values of the slave-boson fields and the explicit expression for the derivative of the adiabatic potential of the system with respect to the counting fields. Performing perturbative expansion to the first order of $\lambda$, we find an extra contribution to the shot noise due to the bias-induced Bose field fluctuation, and then confirm that the nonequilibrium particle number fluctuation plays an important role in the current noise of the Kondo dot: enhancement of the current auto-correlation and a positive current cross-correlation.