Quantum Messages Travel 254 km Using Existing Infrastructure For the First Time (phys.org)
- Reference: 0177112933
- News link: https://science.slashdot.org/story/25/04/23/2227211/quantum-messages-travel-254-km-using-existing-infrastructure-for-the-first-time
- Source link: https://phys.org/news/2025-04-quantum-messages-km-infrastructure.html
> 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.
The research has been [2]published in the journal Nature .
[1] https://phys.org/news/2025-04-quantum-messages-km-infrastructure.html
[2] https://www.nature.com/articles/s41586-025-08801-w
Watch it! (Score:2)
2 more kilometers and you're back to zero.
Re: (Score:2)
Zero? You must be using the wrong codec, buddy!
This one's H.254 (where H is Planck's constant).
Can somebody please explain the point? (Score:2)
... with a concrete example.
So you are talking to a remote person. All you need is a pre-shared key in order to exchange session keys.
If you don't have any pre-shared key, then how on earth can you authenticate? How do you know you are doing Quantum key distribution with the right person?
Surely it is only resistant to MitM attacks if you trust the endpoint. And by what method can you trust the authentication, which does not also provided easier session key exchange than Quantum Buzzwords?
Re: (Score:2)
Sorry my friend, but nobody here has the slightest idea how entanglement works, let alone quantum physics. Nevertheless, the idea is that, traditionally, even the best encryption does not guarantee that the message hasn’t been intercepted. By using quantum entanglement, the recipient of the message is guaranteed that it has not been intercepted (or, conversely, that it has been).
This paper's main contribution (Score:2)
Existing methods for coherence-based quantum key distribution rely on ultra-stable optical cavities and cryogenic photon detectors, which limit scalability and practical deployment.
This study replaces that setup with a non-cryogenic, scalable system using off-band phase stabilization and commercial telecom infrastructure, yet still achieves 254 km secure key distribution, effectively doubling the practical distance for real-world QKD (according to the authors).
That's great! (Score:2)
Now they just need to make it still work after someone *cough*Russia*cough*China*cough* has cut the fibre.
Not instantaneous communication, alas (Score:2)
"though quantum particles that are entangled appear to interact with each other instantaneously — no matter the distance and thus moving at the speed of light — modern science’s understanding of quantum mechanics interprets that it is impossible to transmit data using quantum entanglement."
https://thequantuminsider.com/2023/02/20/quantum-entanglement-communication/#:~:text=Even%20so%2C%20though%20quantum%20particles,transmit%20data%20usin