Counting statistics and decoherence in coupled quantum dots

TL;DR

This paper analyzes charge transport in coupled quantum dots, highlighting how quantum coherence influences statistical properties like noise and skewness, and explores the transition from coherent to incoherent tunneling.

Contribution

It provides a theoretical framework for understanding full counting statistics in quantum dot systems, emphasizing the role of quantum coherence and decoherence effects.

Findings

Quantum coherence significantly affects zero-frequency cumulants.

A continuous transition from coherent to incoherent tunneling is demonstrated.

Decoherence effects are compared using a dephasing voltage probe model.

Abstract

We theoretically consider charge transport through two quantum dots coupled in series. The corresponding full counting statistics for noninteracting electrons is investigated in the limits of sequential and coherent tunneling by means of a master equation approach and a density matrix formalism, respectively. We clearly demonstrate the effect of quantum coherence on the zero-frequency cumulants of the transport process, focusing on noise and skewness. Moreover, we establish the continuous transition from the coherent to the incoherent tunneling limit in all cumulants of the transport process and compare this with decoherence described by a dephasing voltage probe model.