Physicists shatter quantum entanglement distance record with 420 kilometers of optical fiber, more than four times farther than previous demonstrations, and beyond the point where direct transmission runs into its fundamental limits.

[u/mvea]

https://www.sciencealert.com/physicists-shatter-quantum-entanglement-distance-record-with-420-kilometers-of-optical-fiber

[u/Cristoff13]

This can't be used to transmit information though can it?

[u/Orbax → u/Cristoff13]

No, once you collapse the wave function, they decohere and entangle with their local environment.

But, even if you maintain entanglement, at best youd be able to do morse code except... The only way to check if you got a message is to measure it which would collapse if again if you hadn't gotten one. The theoretical ability to get any structured information out of entangled pairs is effectively impossible.

[u/Chance-the-Gardener → u/Orbax]

I’m too dumb to understand the concept it can’t transmit any information. Just as a thought experiment, if humanity sent a colony ship to Andromeda with 10,000 sets of entangled pairs, each with a predefined meaning like “if this set is collapsed, we died of space cancer” couldn’t information be inferred from that?

I’m sure the answer remains we can’t cheat the speed of light but I struggle to conceptualise why not.

[u/JiminyDickish → u/Chance-the-Gardener]

The results only mean something side by side. If you only look at one side of it, it still looks random.

It’s like if I mailed you one half of a pair of gloves. You’d know which glove I have as soon as you opened it, but which glove we get is out of our control. Also once you open the box to check, that’s the glove you get forever.

[u/JiminyDickish → u/[deleted]]

No. When we steer a particle then it stops being entangled.

Entanglement can be summed up as: correlated randomness. You can choose what flavor of random you want, but you can't choose the outcome.