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I Understanding Continuous Variable QKD

  1. Nov 16, 2017 #1
    So, I am doing my undergraduate research project in Quantum Cryptography, and I have some confusion in a few areas, especially in the topic of continuous variable quantum key distribution.

    From what I understand,
    Discrete Variable - Single photon. That is, for example, the BB84 protocol. Bob is measuring 1 photon at a time.
    Continuous Variable- Alice encodes key bits (is it more than 1 bit of the key?) in the quadrature X and P.

    I understand that is Bob measures in the right quadrature in the BB-84 protocol, then he'll get the right corresponding bit. However, if he chooses the wrong quadrature, he'll get the right bit 50% of the time.

    But in CV-QKD, if Bob chooses the right quadrature either X or P, then he'll get the right information, but what happens if he chooses the wrong quadrature?

    One more question, in continuous-variable QKD, what is the difference between coherent states and squeeze states. I understand that squeeze states either increase or decrease the certainty in the quadrature X and P because of the uncertainty principle. Is coherent states still used in DV-QKD (similar to weak pulses)?

    Thanks for your help!
  2. jcsd
  3. Nov 22, 2017 #2
    Thanks for the thread! This is an automated courtesy bump. Sorry you aren't generating responses at the moment. Do you have any further information, come to any new conclusions or is it possible to reword the post? The more details the better.
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