this post was submitted on 20 Mar 2025
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This milestone marks the first-ever quantum satellite communication link established in the Southern Hemisphere.

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[–] NarrativeBear@lemmy.world 6 points 20 hours ago (2 children)

Very cool, I wonder if a quantum link like this needs a clear line of sight. What would be the limits of quantum communication like this? It would be amazing to be able to achieve real time communication between planetary bodies for example.

[–] vic_rattlehead@lemmy.world 11 points 17 hours ago (2 children)

This is not a "quantum entangled data link", it is a regular radio data link secured using quantum computing to generate encryption keys.

[–] LodeMike@lemmy.today 2 points 12 hours ago (1 children)
[–] febra@lemmy.world 3 points 7 hours ago (1 children)

Because you can use one time pad encryption which is theoretically unbreakable. Intercepting the photons used to generate these keys would instantly alter their state thus making them unusable.

[–] LodeMike@lemmy.today 0 points 4 hours ago

oh right one time pad.

It really does feel like you could do this in a better way, though.

[–] rottingleaf@lemmy.world 2 points 14 hours ago

I've read some weird paper about such an analog channel, where something quantum on both sides was used to create another analog signal used kinda as an encryption key. Stumbled upon it trying to understand some things about optics long ago.

[–] ViperActual@sh.itjust.works 11 points 19 hours ago (2 children)

Quantum entanglement/teleportation does not mean information transmission exceeds the speed of light. You're still limited to sending entangled particles to your destination following the laws of physics. You cannot transmit information via this phenomenon.

What you can use this for is transmission integrity. Where you will know if an outside observer intercepted your transmission then sent it on its way to the destination. This is more commonly known as a man in the middle attack (MitM).

[–] fyzzlefry@retrolemmy.com 4 points 19 hours ago (1 children)

Adversary in the middle is the updated terminology. Not just because sex, but also bots and AI.

[–] ViperActual@sh.itjust.works 1 points 18 hours ago

Ooo thank you, I'm definitely out of date by now

[–] NarrativeBear@lemmy.world 3 points 18 hours ago (1 children)

I always imagined quantum entangled particles would be useful in information transmission. Probably not directly, such as the particles transmiting the information themselves, but in a way potentially vibrating a particle on one end and getting the same vibrations on the other end. Depending on the vibrations you deduced the information.

Obviously sending one of the entangled particles to another destination would be as slow as the fastest mode of transport.

But i wonder if we had a entangled communication device on either of the voyages probes if we would be able to send commands to them from earth with no lag in transmission.

[–] LostXOR@fedia.io 2 points 16 hours ago

Quantum entangled particles can't influence each other; they just allow you to infer information about one particle by observing the other. It's like if you randomly put a red and a blue ball in two different boxes without looking, then moved them far apart. Opening one box and seeing a red ball instantly tells you the other box has a blue ball, no matter the distance, but no information has been transmitted faster than the speed of light (because the boxes can only move slower than light).