A telecom-wavelength quantum repeater node based on a trapped-ion processor

TL;DR

This paper demonstrates a quantum repeater node using trapped ions that can establish and extend entanglement over 50 km of optical fiber, paving the way for long-distance quantum networks.

Contribution

It introduces a trapped-ion based quantum repeater node capable of entanglement distribution and swapping over 25 km fibers, with system improvements projecting over 800 km.

Findings

Successfully established entanglement over 50 km fiber channels.

Demonstrated entanglement swapping to extend distance.

Projected chain capabilities for 800 km entanglement distribution.

Abstract

A quantum repeater node is presented based on trapped ions that act as single photon emitters, quantum memories and an elementary quantum processor. The node's ability to establish entanglement across two 25 km-long optical fibers independently, then to swap that entanglement efficiently to extend it over both fibers, is demonstrated. The resultant entanglement is established between telecom-wavelength photons at either end of the 50 km channel. The system improvements to allow for repeater-node chains to establish stored entanglement over 800 km at Hertz rates are calculated, revealing a near-term path to distributed networks of entangled sensors, atomic clocks and quantum processors.