China Shatters “Spooky Action at a Distance” Record, Preps for Quantum Internet

Discussion in 'Science' started by alfster, Jun 16, 2017.

  1. alfster

    alfster Member

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    Last edited: Jun 16, 2017
  2. Hater

    Hater Member

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    Unhackable?

    Brave word.
     
  3. RobRoySyd

    RobRoySyd Member

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    Einstein agrees with you. It's one of the few things he's been proven wrong about.
     
  4. Matthew kane

    Matthew kane Member

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    Errr what?
     
  5. dakiller

    dakiller (Oscillating & Impeding)

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    Probably poor journalism to be using that word, but in a sense this is technology that has communication that cannot be eavesdropped on without the people communicating knowing about it, which is a product of the laws of physics.

    I started writing what I know about quantum entanglement, but I think Wikipedia explains it succinctly enough.

     
  6. RobRoySyd

    RobRoySyd Member

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    Einstein and others couldn't accept the spooky action at a distance of quantum entanglement. Instead they proposed that there were hidden variables that would define the entire state of the system.

    Hidden variable theory.


    The more relevant aspect of entanglement is it gives rise to the "no clone rule". So systems such as PRISM just will not work. Not so say that entangled photons cannot be relayed, they can be so long as they're not "read" i.e. collapsed. This is what China has got to work over several repeaters. It's still not very practical as almost all of the entangled photons sent from the satellite are lost in the atmosphere, data throughput is low.
     
  7. Smoke87

    Smoke87 Member

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    Major flaw in the 'unhackable' theory; it requires the use of a one-time pad and pre-shared key to ensure both integrity/authenticity and confidentiality of the message sent. This actually applies to present day communications.

    The journalist was trying to say that this technology will permit us to know when the message has been intercepted along the way, but this would I think still require a one-time pad or prior knowledge of the message sent. As the latter renders the concept useless, only a one time pad provides a basis for this to work.

    What I expect is that there would be 'padding' added to either end of the message and only these would be necessary to be known to both the sender and receiver, thereby increasing the efficiency of said one-time-pad. Still, I don't think this is necessarily groundbreaking.

    Also, I won't believe it until I see it reproduced entirely independently by European, Japanese or American scientists.

    Bloody hell, imagine the margin for error :| I do hope they don't operate on the presumption that its entirely impossible for their message to have not been reproduced by natural phenomena. If they got one pair for every 6 billion in a second, I suppose a sustained test over a long period of time with a high complex message known at both locations would rule this out?
     
    Last edited: Jun 23, 2017
  8. elh9

    elh9 Member

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    A nice side effect of attempting hacking this system will be gaining some knowledge on quantum physics/mechanics :p

    Maybe the first hacker of the quantum internet is going to be some quantum physics PhD student doing their thesis :p
     
  9. Cererus

    Cererus Member

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    For the non quantum savvy, how are the entangled photons "held" both on the ground in China and in the satellite, i assume its more complicated than just putting it in a jar.
     
  10. RobRoySyd

    RobRoySyd Member

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    You just need the right kind of jar :)

    Cavities Play Catch with Photons.

    At unity efficiency the cavity would be a perfect "jar".

    They've not done anything others thought impossible or even improbable. They've just succeeded in doing it better.
     
  11. PRiME2007

    PRiME2007 Member

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    I was watching a video about this kind of particle behavior being part of strong evidence that our perceivable universe is actually a big VR simulation (and likely us also) because the particles act in a easier to process method (wave motion) when not observed, but when you look at them close it gets detailed and changes its behavior.

    I know that's old news but its a interesting argument non the less, I mean when you think about it, why should particles care who is watching them and when? but they do....

    PS. I know its more complicated then how I explained it. But because physicists still can't explain or agree on what's really happening, it leaves the whole VR universe theory on the table.
     
  12. OP
    OP
    alfster

    alfster Member

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    I saw a show on Foxtel about this Prime2007, the particles behave differently whether anyone is observing them or not, sometimes they are waves & sometimes particles. It seems time can be reversed as well depending on when the scientists decide to look. Spooky action at a distance is literally the weirdest thing I have ever heard of, the scientists haven't got a clue what's going on either.

    A big VR simulation you think? Who knows. I lean towards multi universes & multi dimensions myself, but I'm just an average Joe, I didn't even do physics in high school.
     
  13. RobRoySyd

    RobRoySyd Member

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    What the theory proposes is observation causes the wave function to collapse.
    This isn't just something that happens with photons, it can be made to happen with electrons or even atoms and with great care molecules. Truly weird.

    I gets weirder. Consider what will happen to my lab rat Alice when I let her fall into a black hole. According to her frame a reference Alice will be just fine, at least just inside the event horizon. According to my frame of reference she's toast.

    Logically she cannot be both so how to determine is Alice alive or dead?
    It can be done but I'd need a very powerful source of photons, some massive laser. Armed with that I will determine my prediction correct as I toasted poor Alice with my laser. :( Our universe is a grand conspiracy that we may never fully understand beyond doubt.
     
  14. PRiME2007

    PRiME2007 Member

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    Either way we seem to be all just play things in this grand scheme (VR). :wired:
     

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