Quantum cellular Automata

overwhelmedblueearthAI and Robotics

Dec 1, 2013 (3 years and 8 months ago)

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S. E. Thompson EEL 6935

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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.


S. E. Thompson EEL 6935

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Quantum cellular Automata


4 quantum SED dot


2 electrons added to system


System will minimize electro
-
static energy

0

1

S. E. Thompson EEL 6935

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Quantum cellular Automata :Example


Input

1

Propagate a 1

S. E. Thompson EEL 6935

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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

S. E. Thompson EEL 6935

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Quantum cellular Automata : Logic Gate
example


Input A

0

Propagate a 0


Input C


Input B

0

0

1

Voting gate

S. E. Thompson EEL 6935

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

S. E. Thompson EEL 6935

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S. E. Thompson EEL 6935

Ferroelectric RAM

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DRAM