3 ms·

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

28 points by donutloop 10mo ago

bradrn 10mo ago
> extremely cold temperatures (267 °C) Sorry? (I have a feeling someone meant Kelvin, though 267 K is hardly ‘extremely cold’ either…)
- ginko 10mo ago
  Maybe a negative sign got dropped?
  - nels 10mo ago
    Seems like you're right! [1] [1] https://studyfinds.org/physicists-pull-off-quantum-teleportation-using-existing-internet-technology/#:~:text=experiments%20required%20extremely%20cold%20temperatures%20(about%20%E2%80%91267°C) https://studyfinds.org/physicists-pull-off-quantum-teleporta...
- fhdkweig 10mo ago
  negative 267 C would be 6 Kelvin ???
  - zifk 10mo 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.
darkfloo 10mo 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
- ben_w 10mo 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.
vrighter 10mo 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?

28 points by donutloop 10mo ago

bradrn 10mo ago

> extremely cold temperatures (267 °C) Sorry? (I have a feeling someone meant Kelvin, though 267 K is hardly ‘extremely cold’ either…)

ginko 10mo ago
Maybe a negative sign got dropped?
- nels 10mo ago
  Seems like you're right! [1] [1] https://studyfinds.org/physicists-pull-off-quantum-teleportation-using-existing-internet-technology/#:~:text=experiments%20required%20extremely%20cold%20temperatures%20(about%20%E2%80%91267°C) https://studyfinds.org/physicists-pull-off-quantum-teleporta...
fhdkweig 10mo ago
negative 267 C would be 6 Kelvin ???
- zifk 10mo 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.

darkfloo 10mo 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

ben_w 10mo 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.

vrighter 10mo 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?