Full counting statistics for the Kondo dot in the unitary limit

TL;DR

This paper derives the full counting statistics of charge transfer in a Kondo quantum dot at strong coupling, revealing universal charge fluctuation laws and analyzing crossover behavior from weak to strong interactions.

Contribution

It provides a theoretical calculation of charge transfer statistics in the Kondo regime using Fermi-liquid theory, including universal laws and temperature effects.

Findings

Universal ratio of charge distribution moments to backscattering current.

Functional form of charge transfer distribution consistent with electron tunneling and pairing.

Analysis of crossover from weak to strong Coulomb interactions.

Abstract

We calculate the charge transfer probability distribution function $\chi(\lambda)$ for the Kondo dot in the strong coupling limit within the framework of the Nozi\`{e}res--Fermi--liquid theory of the Kondo effect. At zero temperature, the ratio of the moments $C_n$ of the charge distribution to the backscattering current $I_{{\rm bs}}$ follows a universal law $C_n/2I_{{\rm bs}}=(-1)^n(1+2^n)/6$. The functional form of $\chi(\lambda)$ is consistent with tunnelling of electrons and, possibly, electron pairs. We then discuss the cross-over behaviour of $\chi(\lambda)$ from weak to strong Coulomb repulsion in the underlying Anderson impurity model and relate this to the existing results. Finally, we extend our analysis to the case of finite temperatures.