Long-distance quantum link generates entanglement faster than it is lost
Summary
Researchers report creating entanglement between two trapped ions connected by long stretches of telecommunications optical fibre — reportedly up to 101 kilometres of spooled fibre. Crucially, the team generated entanglement at a rate that outpaces the loss and decoherence in the link, a key milestone for building scalable quantum-communication networks and quantum repeaters. This advance brings practical long-range quantum links closer to reality and strengthens prospects for secure quantum communications and distributed quantum devices.
Key Points
- Entanglement was demonstrated between two trapped ions separated by very long spans of telecom optical fibre (reported up to 101 km).
- The experiment produced entanglement faster than it was lost to transmission and decoherence — a crucial threshold for scalable quantum networks.
- Achievement is a major step towards practical quantum repeaters, which are needed to extend quantum links over continental distances.
- Uses existing fibre-infrastructure concepts (spooled telecom fibre here) as a testbed for future deployed networks.
- The result strengthens the practical case for quantum communications technologies such as unbreakable encryption and distributed quantum sensors/computers.
Context and relevance
This News & Views piece summarises the Liu et al. result published in Nature: it situates the experiment as a milestone in the long-running effort to build quantum repeaters and a quantum internet. Demonstrating that entanglement generation can exceed loss over long fibre is the technical threshold that moves lab demonstrations closer to real-world deployment. For researchers and engineers in quantum communications, the work marks tangible progress on scaling entangled links beyond short laboratory distances.
Why should I read this?
Quick and simple: if you care about the quantum internet actually happening (not just hype), this shows the maths and engineering are catching up. They got entanglement rates above the loss rate over telecom fibre — the sort of thing that turns a neat demo into something you might one day route down a real cable. Read it if you want the short version of why quantum networks might stop being a lab curiosity and start becoming infrastructure.
Author style
Punchy: the authors make clear this is a meaningful, hard-won technical advance — essential reading if you follow quantum networking and communications.
Competing interests
Note: one author (RH) is co-founder and shareholder of Delft Networks B.V., which develops quantum-network technology.