From sci-fi to reality: Researchers realise quantum teleportation using tech

Posted by donutloop 1 day ago

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Comment by bradrn 23 hours ago

> extremely cold temperatures (267 °C)

Sorry?

(I have a feeling someone meant Kelvin, though 267 K is hardly ‘extremely cold’ either…)

Comment by fhdkweig 23 hours ago

negative 267 C would be 6 Kelvin ???

Comment by zifk 23 hours ago

That's pretty standard for experimental quantum systems. A lot run on helium fridges at 4K. The superconducting stuff even colder, in 10 mK dilution fridges.

Comment by ginko 23 hours ago

Maybe a negative sign got dropped?

Comment by nels 22 hours ago

Seems like you're right! [1]

[1] https://studyfinds.org/physicists-pull-off-quantum-teleporta...

Comment by vrighter 13 hours ago

Why does the title have part of it omitted? It completely changes the meaning.

Now it reads as "someone built something using tools". What tools? Why is using tools newsworthy?

Comment by darkfloo 22 hours ago

Anyone better at physics than me willing to explain how this does not break general relativity ? I might be missing the point of the experiment completely to be fair

Comment by ben_w 22 hours ago

Nobody has fully combined GR and QM, but the ELI5 summary of the best efforts is:

There's no paradox from quantum state being transmitted faster than light, because quantum state is, fundamentally, not directly measurable.

This may lead to a follow up question of "OK, so why do we even care?", to which the answer is that the relevant quantum state (the entanglement bit of it) causes correlations in other measurements. If you only read off the measurable value of an entangled particle, you know nothing. If you do a quantum teleportation, you also send information in a non-quantum channel, which you can combine with reading the entangled particle, and with both you now know more than you knew from just the non-quantum channel.

In the case of internet encryption, this mainly means sending a random key and knowing it hasn't been intercepted, because any interception would break that correlation.

Because a quantum teleportation must also send information classically, it's never FTL.