Distinguishing coherent from incoherent charge transport in linear triple quantum dots

TL;DR

This paper investigates how quantum coherence affects charge transport in linear triple quantum dots by comparing different theoretical models and analyzing statistical measures, revealing that shot noise and skewness can indicate coherence effects.

Contribution

It introduces a comparative analysis of Lindblad and Pauli models for quantum dots and demonstrates how shot noise and skewness can serve as indicators of coherence in charge transport.

Findings

Shot noise and skewness are sensitive to quantum coherence.

Coherent processes can be unambiguously identified using statistical measures.

Analytical full counting statistics are derived using the characteristic polynomial approach.

Abstract

A fundamental question in quantum transport is how quantum coherence influences charge transfer through nanostructures. We address this issue for linear triple quantum dots by comparison of a Lindblad density matrix description with a Pauli rate equation approach and analyze the corresponding zero-frequency counting statistics for coherent and sequential charge tunneling, respectively. The impact of decaying coherences of the density matrix due to dephasing is also studied. Our findings reveal that the sensitivity to coherence shown by shot noise and skewness, in particular in the limit of large coupling to the drain reservoir, can be used to unambiguously evidence coherent processes involved in charge transport across triple quantum dots. Our analytical results are obtained by using the characteristic polynomial approach to full counting statistics.