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CNOT gate

  1. Aug 25, 2004 #1

    Mk

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    Yeah so, scientists in Japan have the CNOT gate, control not. What does it do? What's the truth table... other stuff. Are gates made of transistors?
     
  2. jcsd
  3. Aug 26, 2004 #2

    chroot

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    Could you please provide some context? I have no idea what you're talking about.

    - Warren
     
  4. Aug 26, 2004 #3

    cronxeh

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  5. Aug 26, 2004 #4
    Mk, is talking about Quantum-Information-Technology, chroot. The CNOT gate is one of them reversible gates, and it is also named the reversible XOR-gate. Basically the gate flips the second bit if the first is 1 and does nothing if the first bit is zero (hence the name controlled-not).

    This gate performs a NOT on the second bit if the first bit is set to 1 and it performs a copy-operation if the second bit is initially set to 0.


    The problem is that all these one-bit and twobit gates are non-universal, they cannot compute any operation using just the gate in question. The "first" universal gate is the three-bit Toffoli-gate or the controlled-controlled-NOT-gate.

    It computes : (x,y,z) ---->(x,y,z + xy) where the sum is the sum modulo 2

    This gate performs all the operations (NAND, COPY) necessary to be universal...

    regards
    marlon
     
  6. Aug 26, 2004 #5

    Mk

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    Thanks a lot. Exactly what I needed... but I'm not sure about the CNOT is the XOR. XOR aka EOR (eyore, the donkey!), is eXclusive OR. XOR gives a true if either A and B but not both, are true.
     
  7. Aug 26, 2004 #6
    The CNOT gate is just the same as the reversible XOR-gate


    regards
    marlon
     
  8. Aug 26, 2004 #7

    Mk

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    Ahhh! I see. :smile:
     
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