Quantum cellular Automata

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Quantum cellular Automata

• Quantum Cellular Automata (QCA) refers to any one
  of several models of quantum computation, which
  have been devised in analogy to conventional
  models of cellular automata introduced by von
  Neumann. It may also refer to quantum dot
  cellular automata, which is a proposed physical
  implementation of "classical" cellular automata
  by exploiting quantum mechanical phenomena.

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Quantum cellular Automata
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0

• 4 quantum SED dot
• 2 electrons added to system
• System will minimize electro-static energy

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Quantum cellular Automata Example
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Propagate a 1

• Input

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Quantum cellular Automata Logic

• Based on neighbor interaction
• Vs movement of charge
• Key advantages
• Very low power
• Key disadvantage
• No gain.
• Input not isolated from output

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Quantum cellular Automata Logic Gate example

• Input A

• Input B

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0
0
Propagate a 0
0

• Input C

Voting gate
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An Inverter
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History

• Proposed in 1993 by Lent et. al.
• Based on ground state computation
• System moves to lowest electro-static energy
  state
• State of lowest energy uniquely defined
• Key issue is energy level between states and kT.
• 1997 physical implementation of QCA produced
• Tunnnel junctions and Al islands
• Experiment at 10mK

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Ferroelectric RAM
DRAM