Dephasing-assisted transport in linear triple quantum dots

TL;DR

This paper demonstrates that pure dephasing can enhance charge transport in linear triple quantum dots, with the effect controllable via coupling to the drain, and identifies underlying quantum dynamical processes.

Contribution

It provides analytical insights into dephasing-assisted transport in quantum dots, highlighting conditions for enhancement and the role of quantum Zeno effect and tunnelling.

Findings

Dephasing enhances current when drain coupling exceeds a threshold.

Enhanced transport is controllable by drain coupling strength.

Long-distance tunnelling and quantum Zeno effect are key mechanisms.

Abstract

Environmental noise usually hinders the efficiency of charge transport through coherent quantum systems; an exception is dephasing-assisted transport (DAT). We show that linear triple quantum dots in a transport configuration and subjected to pure dephasing exhibit DAT if the coupling to the drain reservoir exceeds a threshold. DAT occurs for arbitrarily weak dephasing and the enhancement can be directly controlled by the coupling to the drain. Moreover, for specific settings, the enhanced current is accompanied by a reduction in relative shot noise. We identify the quantum Zeno effect and long-distance tunnelling as underlying dynamical processes involved in dephasing-assisted and -suppressed transport. Our analytical results are obtained by using the density matrix formalism and the characteristic polynomial approach to full counting statistics.