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Superluminal Communications

  1. Nov 16, 2015 #1
    How is quantum entanglement used in superluminal communications? I'm not sure whether I have the right idea of quantum entanglement (and if I do not, please correct me), but I wonder how quantum entanglement is used if the particles in entanglement are autonomous (that is to say, they can't be tampered along with maintaining the entanglement between the particles).
     
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  3. Nov 16, 2015 #2

    phinds

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    It is not. Entanglement is not useful in exchanging information. There is no such thing as superluminal communication.
     
  4. Nov 16, 2015 #3

    DrChinese

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    Welcome to PhysicsForums, quantum.cmptr!

    As far as anyone know, superluminal (FTL) communication is not possible, neither using entanglement nor any other mechanism.
     
  5. Nov 16, 2015 #4
    Thanks for all the answers!
     
  6. Nov 16, 2015 #5
    Actually, what are some ways quantum communications work? I know this sounds a bit broad, but I'm curious on how it works.
     
  7. Nov 16, 2015 #6

    phinds

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  8. Nov 16, 2015 #7
    That definitely is too broad, what exactly do you mean by 'quantum communications'
    One field of communications which quantum computing is expected to improve dramatically is the field of encryptation,
    also other applications.where security, 'hack-proofing', is a priority.
     
  9. Nov 16, 2015 #8
    I apologize for the incorrectly phrased question. What I meant was quantum cryptography.
     
  10. Nov 16, 2015 #9

    phinds

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    And what research have you done so far? What have you found out?
     
  11. Nov 16, 2015 #10
    All I know is that its just a new way of encryption, and that this is supposed to be harder to actually crack in comparison to current widely-used methods.
     
  12. Nov 16, 2015 #11
  13. Nov 16, 2015 #12
  14. Nov 17, 2015 #13

    Simon Phoenix

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    What you're really talking about here is quantum key distribution (QKD). This is not an encryption method, but a way of establishing a shared secret between two people, in such a way that the security of their shared secret can be given strict bounds. The shared secret data can then be used as a key for cryptographic purposes.

    The 'Holy Grail' of QKD is to get the key establishment rate fast enough so that we can use the One Time Pad as the encryption method to encrypt the data. The OTP is provably secure.

    In security terms, then, what needs to be compared is the security of classical key distribution methods vs the quantum key distribution method. The difficulty for QKD is that in terms of a security risk assessment the threat posed to conventional classical key distribution methods is not judged to be severe currently. In other words it's not seen as a weak link in the security chain.

    This threat model changes when quantum computing becomes available because many of the conventional classical key exchange mechanisms used today rely on public key cryptography, the most popular forms of which are vulnerable to quantum computers. If someone built a working quantum computer tomorrow we'd have a financial meltdown. It really is that serious because almost all of the interactions on the internet (and other networks such as the SWIFT banking network) rely in part on public key techniques that are vulnerable to quantum computation. There has been a lot of work done in trying to figure out new encryption algorithms that are resistant to attack by a quantum computer - and it's known as quantum-safe encryption.
     
  15. Nov 19, 2015 #14
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