Full counting statistics for the Kondo dot in the unitary limit

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.