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aliks [soylentnews.org] writes:

The story itself is interesting as quantum messaging over existing networks dramatically reduces costs, but I wanted to compare how different sources report the story.

The story caught my eye on phys.org where you get a short but reasonal summary with pictures. Maybe phys.org used AI to generate this summary?

scienmag.com has a longer summary with more detail and commentary on why the story is significant.

The original story is reported in Nature, with more detail and dense technical language.

First off we have phys.org: https://phys.org/news/2025-04-quantum-messages-km-infrastructure.html [phys.org]

"Quantum messages travel 254 km using existing infrastructure for the first time

by Nature Publishing Group
Deployed coherent quantum communications system. Credit: Nature (2025). DOI: 10.1038/s41586-025-08801-w

Quantum messages sent across a 254-km telecom network in Germany represent the first known report of coherent quantum communications using existing commercial telecommunication infrastructure.

The demonstration, reported in Nature this week, suggests that quantum communications can be achieved in real-world conditions.

Quantum networks have the potential to enable secure communications, such as a quantum internet; quantum key distribution is one example of a theoretically secure communication technique.

Exploiting the coherence of light waves (their potential to interact predictably) can extend the range of quantum communications, but scalability has been limited by the need for specialized equipment, such as cryogenic coolers.

An approach that enables the distribution of quantum information through optical fiber cables, without the need for cryogenic cooling, is described by Mirko Pittaluga and colleagues.

Their system uses a coherence-based twin-field quantum key distribution, which facilitates the distribution of secure information over long distances.

The quantum communications network was deployed over three telecommunication data centers in Germany (Frankfurt, Kehl and Kirchfeld), connected by 254 km of commercial optical fiber—a new record distance for real-world and practical quantum key distribution, according to the authors.

This demonstration indicates that advanced quantum communications protocols that exploit the coherence of light can be made to work over existing telecom infrastructure."

Next we have https://scienmag.com/quantum-communication-achieves-long-distance-telecom-integration/ [scienmag.com] which is too long to quote in full - first para reads:

"In the rapidly evolving domain of quantum communications, the ability to maintain optical coherence over long distances has emerged as a vital ingredient for constructing the quantum internet of the future. Recent groundbreaking work by Pittaluga and colleagues marks a significant leap forward in this area, demonstrating coherent quantum communication over an unprecedented 254-kilometer span of deployed commercial fiber optic infrastructure connecting Frankfurt and Kehl in Germany. This achievement not only sets a new benchmark for distance in quantum key distribution (QKD) but also showcases the potential for integrating advanced quantum protocols within existing telecommunications frameworks without reliance on bulky cryogenic technology."

And finally the Nature abstract: https://www.nature.com/articles/s41586-025-08801-w [nature.com]

"Recent advances in quantum communications have underscored the crucial role of optical coherence in developing quantum networks. This resource, which is fundamental to the phase-based architecture of the quantum internet, has enabled the only successful demonstrations of multi-node quantum networks and substantially extended the range of quantum key distribution (QKD). However, the scalability of coherence-based quantum protocols remains uncertain owing to the specialized hardware required, such as ultra-stable optical cavities and cryogenic photon detectors. Here we implement the coherence-based twin-field QKD protocol over a 254-kilometre commercial telecom network spanning between Frankfurt and Kehl, Germany, achieving encryption key distribution at 110 bits per second. Our results are enabled by a scalable approach to optical coherence distribution, supported by a practical system architecture and non-cryogenic single-photon detection aided by off-band phase stabilization. Our results demonstrate repeater-like quantum communication in an operational network setting, doubling the distance for practical real-world QKD implementations without cryogenic cooling. In addition, to our knowledge, we realized one of the largest QKD networks featuring measurement-device-independent properties. Our research aligns the requirements of coherence-based quantum communication with the capabilities of existing telecommunication infrastructure, which is likely to be useful to the future of high-performance quantum networks, including the implementation of advanced quantum communication protocols, quantum repeaters, quantum sensing networks and distributed quantum computing."

Original Submission