Measurement-based quantum repeaters

TL;DR

This paper proposes measurement-based quantum repeaters that use small entangled states and simple Bell measurements to enable long-distance quantum communication with improved noise tolerance and minimal resource requirements.

Contribution

It introduces a novel measurement-based approach to quantum repeaters, reducing resource size and enhancing noise thresholds for practical quantum communication.

Findings

Measurement-based purification protocols have higher noise thresholds.

Small resource states can significantly extend communication distances.

The scheme simplifies quantum repeater implementation with fewer quantum gates.

Abstract

We introduce measurement-based quantum repeaters, where small-scale measurement-based quantum processors are used to perform entanglement purification and entanglement swapping in a long-range quantum communication protocol. In the scheme, pre-prepared entangled states stored at intermediate repeater stations are coupled with incoming photons by simple Bell-measurements, without the need of performing additional quantum gates or measurements. We show how to construct the required resource states, and how to minimize their size. We analyze the performance of the scheme under noise and imperfections, with focus on small-scale implementations involving entangled states of few qubits. We find measurement-based purification protocols with significantly improved noise thresholds. Furthermore we show that already resource states of small size suffice to significantly increase the maximal communication distance. We also discuss possible advantages of our scheme for different set-ups.