Large Spin Entangled Current from a Passive Device

TL;DR

This paper demonstrates a passive quantum device using three resonant quantum dots that can generate a large entangled electron current, with potential applications in quantum communication and security.

Contribution

It introduces a simple, passive quantum dot device capable of producing high-rate entangled electron currents with tunable modes and robustness for experimental realization.

Findings

High entangled current achievable with the device

Device operates in both 'clean' and 'dirty' modes

Charge detection can improve entanglement quality

Abstract

We show that a large entangled current can be produced from a very simple passive device: a cluster of three resonant quantum dots, tunnel coupled to one input lead and two output leads. The device can function in a `clean' mode, when almost all emitted electrons are paired in Bell states, or a `dirty' mode with a far higher emission rate but a significant portion of non-entangled electrons. Subsequent charge detection can enhance performance by identifying the pairs that are most likely to be entangled. The device is robust to specific choice of system parameters and therefore lends itself to immediate experimental demonstration. Applications include quantum repeaters and unconditionally secure interfaces.