Quantum Computing: the final presentation

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Quantum Computingthe final presentation

• Presented by
• The guy with the beard, (Lee Ballard)
• The guy without the beard, (Hey, I do have a
  beard.)
• And (Sort of.)
• The girl who doesnt present. (Amanda Denton)

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Logic Gates
Basic Logic Gates
Not
And
Or
NAnd
NOr
XOr
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Quantum Logic Gates

• Quantum gates are very similar to classical logic
  gates.
• Quantum gates must be reversible due to the
  nature of quantum computing.
• Most classical logic gates are not reversible.
• Only the Not gate can return to the original
  input.

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Other gates are not reversible

• The And Gate
• If output 1
• input 1 and 1
• If output 0
• input could be
• 1 and 0
• 0 and 1
• 0 and 0

We dont know what the input was, therefore it
isnt reversible
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Creating a reversible gate
The value of x the value of a If a 0, then
the value of y the value of b If a 1,
the the value of y the value of NOTb
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The Toffoli Gate
x a b y If a 1 and b 1, then z
NOTc Else, z c
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Applying logic gates to QC

• As shown in an article on the Nature web site,
  scientists have performed a simple NOT operation
  using photons as qubits rather than the charge on
  electrons. This is of interest here because of
  our use of reversible logic.

http//www.nature.com/nsu/021021/021021-4.html
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Building a quantum adder

• To construct a quantum adder, we use our two
  reversible gates (CNOT and the Toffoli gate) to
  add up a couple of bits into a total.
• In the examples given by Glassner, three separate
  1-bit registers are added into two 1-bit
  register, so the 3 inputs can be 0 or 1 and the
  output can be from 0 to 3 (0 to 11)

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Quantum adder

• In Glassners five register example, the logic is
  fairly simple two Toffoli gates and a CNOT gate
  affect the second register or 10s place, and
  the next three CNOT gates set the 1s place.

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Quantum adder
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The Quantum Adder