Full counting statistics of the two-stage Kondo effect

TL;DR

This paper extends full counting statistics to multi-channel Kondo systems, specifically analyzing charge transfer in the two-stage Kondo effect, revealing crossover regimes and proposing new measurement methods.

Contribution

It introduces a theoretical framework for FCS in multi-channel Kondo models and demonstrates it on the two-stage Kondo system, highlighting charge transfer regimes and measurement techniques.

Findings

Fano factor ranges from 1 to 5/3, indicating crossover from Poissonian to super-Poissonian statistics.

Charge transfer exhibits distinct regimes in the two-stage Kondo effect.

Proposes a new method to measure transport properties via charge current and noise.

Abstract

We developed a theoretical framework which extends the method of \textit{full counting statistics} (FCS) from conventional single channel Kondo screening schemes to multi-channel Kondo paradigm. The developed idea of FCS has been demonstrated considering an example of two-stage Kondo (2SK) model. We analyzed the charge transferred statistics in the strong-coupling regime of a 2SK model using non-equilibrium Keldysh formulation. A bounded value of Fano factor, $1\leq F\leq 5/3$, confirmed the cross-over regimes of charge transfered statistics in 2SK effect, from Poissonian to super-Poissonian. An innovative way of measuring transport properties of 2SK effect, by the independent measurements of charge current and noise, has been proposed