Chinese scientists test quantum entanglement over unprecedented distance
scientificamerican.com
Chinese scientists test quantum entanglement over unprecedented distance
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Re: Chinese scientists test quantum entanglement over unprecedented distance
#2I thought quantum entanglement is the idea that two quantum particles separated by distance will behave the same at the same time regardless od distance.
Why is sending photons over distances a verification of quantum entanglement?
Can someone elaborate on what this is?
Re: Chinese scientists test quantum entanglement over unprecedented distance
#3As a child I dreamt of having two futuristic walkie-talkies sharing several pairs of entangled particles making perfect instant communication across the galaxy possible. Later my physics teacher crushed my dreams by telling me it's far from as easy as that and probably impossible due to Heisenberg's ... (no clue what it's called in English).
It's pretty awesome to hear that something similar is actively being worked on and seems possible, although being a huge challenge.
Re: Chinese scientists test quantum entanglement over unprecedented distance
#4The interesting part of "quantum communications" is the impact on security and surveillance. Does "quantum communications" even needs switches and routers? Backdoors don't seem to be possible...
Re: Chinese scientists test quantum entanglement over unprecedented distance
#5I thought quantum entanglement is the idea that two quantum particles separated by distance will behave the same at the same time regardless od distance. Why is sending photons over distances a verification of quantum entanglement? Can someone elaborate on what this is?
Probably it is similar to what has been done here:
http://www.cbc.ca/beta/news/canada/calgary/calgary-teleporta...
Information can't travel faster than the speed of light. You have to actually take the photons and move them away from one another, then check one which will modify both.
Re: Chinese scientists test quantum entanglement over unprecedented distance
#6A staple of sci-fi has been a pair of boxes with quantum entangled particles inside allowing FTL communications once the boxes travel (sub-FTL) to their destination.
By my understanding that's impossible, although I always wondered if you could coordinate FTL, by detecting when a particle was no longer entangled.
Can someone with the background comment?
Re: Chinese scientists test quantum entanglement over unprecedented distance
#7I thought quantum entanglement is the idea that two quantum particles separated by distance will behave the same at the same time regardless od distance. Why is sending photons over distances a verification of quantum entanglement? Can someone elaborate on what this is?
I too am wondering about this. I thought entanglement couldn't be used for communication because observing both particles simultaneously will reveal that they have opposite spins. It's a conformation after observation, based on what the quantum superposition collapses into once you observe the state. But the actual state is also unknown until you observe it.
I'm not a physicist, but I'm sure there're be one on HN that will tell us what this study really means.
Re: Chinese scientists test quantum entanglement over unprecedented distance
#8Wikipedia says:
"If Bohmian Mechanics as an non-local hidden variables interpretation of quantum mechanics is accurate it should allow quantum computers to implement a search of an N-item database at most in O ( N 3 ) {\displaystyle O({\sqrt[{3}]{N}})} steps. This is slightly faster than the O ( N ) O({\sqrt {N}}) steps taken by Grover's algorithm using standard interpretations of quantum mechanics. Neither search method will allow quantum computers to solve NP-Complete problems in polynomial time.[4]"
I thought there was no way to figure out which interpretation of QM is correct. Can someone explain?
Re: Chinese scientists test quantum entanglement over unprecedented distance
#9I thought quantum entanglement is the idea that two quantum particles separated by distance will behave the same at the same time regardless od distance. Why is sending photons over distances a verification of quantum entanglement? Can someone elaborate on what this is?
I too am wondering about this. I thought entanglement couldn't be used for communication because observing both particles simultaneously will reveal that they have opposite spins. It's a conformation after observation, based on what the quantum superposition collapses into once you observe the state. But the actual state is also unknown until you observe it. I'm not a physicist, but I'm sure there're be one on HN tha…
Well, if there is one, you will only know for sure after they reply. It's a conformation after observation too.
Re: Chinese scientists test quantum entanglement over unprecedented distance
#10A staple of sci-fi has been a pair of boxes with quantum entangled particles inside allowing FTL communications once the boxes travel (sub-FTL) to their destination. By my understanding that's impossible, although I always wondered if you could coordinate FTL, by detecting when a particle was no longer entangled. Can someone with the background comment?
It's about as likely as reading a byte from an initialized /dev/urandom and measuring its entropy to see if someone removed a hardware RNG.