[comp.theory.cell-automata] Quantum CA

egnr76@castle.ed.ac.uk (A Kashko) (10/04/90)

	Someone mentioned Quantum Cellular Automata to me today, but could give
no details. Could anyone who knows about them give me references, preferably
including a fairly introductory reference. A quick description of why they are
quantum would also help.
		Thanks in advance
	Alex Kashko
	Dept of Physics
	University of Edinburgh
	Kings Buildings
	Mayfield Road
	Edinburgh
	Scotland

jhaataja@finsun.csc.fi (Juha Haataja) (10/05/90)

In <6578@castle.ed.ac.uk> egnr76@castle.ed.ac.uk (A Kashko) writes:

>	Someone mentioned Quantum Cellular Automata to me today, but could give
>no details. Could anyone who knows about them give me references, preferably
>including a fairly introductory reference. A quick description of why they are
>quantum would also help.

A reference is:

  Quantum Cellular Automata
  Gerhard Grossing, Anton Zeilinger
  Complex Systems 2 (1988) 197-208

Complex Systems is a journal published by Complex Systems Publications, Inc.
A correction to the article above is found in (the figures were not too
good):

  Quantum Cellular Automata: A Corrigendum
  Gerhard Grossing, Anton Zeilinger
  Complex Systems 2 (1988) 611-623

The idea is that when the size of a computing element becomes sufficiently
small, quantum effects cannot be neglected.

I hope this helps.

- Juha Haataja

  ---- Juha Haataja / jhaataja@finsun.csc.fi / EARN: jhaataja at finfun ---
  -------------------------------------------------------------------------
<<  I spent more than 2000 livres on occult books and various experiments. >>
  -------------------------------------------------------------------------

kido@math.keio.ac.jp (Takashi Kido) (10/09/90)

>. .. Can anyone provide references or source code? 

   about  hodge podge simulator.  See Sci Am, ~sept 88.
when you use this program in kcl,you'd better repair next part.

  (shiftf a1 a2) --> (dotimes (i (array-dimension a1 0))
                           (dotimes(j (array-dimension a1 1))
                                 (setf (aref a1 i j)(aref a2 i j))))
                     
                                
                                    by takashi kido
--

                       **************************************
                       $@!v(J  $@7D1~Bg3XM}(J$@9)3XItCf@>8&5f<<(J       $@!v(J  
                       $@!v(J                                   $@!v(J 
                       $@!v(J           $@>k8M(J  $@N4(J $@!J(Jtakashi kido)$@!v(J  
                       ************************************** 
                        

nhm@im.lcs.mit.edu (Norm Margolus) (10/14/90)

Some people talk about Quantum Computation as being computation at a
small length scale that makes use of quantum interference effects.  I
would tend to reserve the term for microscopic systems which don't
rely on constant communication with the macroscopic realm to make them
work.  Although from the point of view of a macroscopic (classical)
observer QM is mainly a source of noise and difficulty, from a
microscopic point of view it provides wonderful possibilities: a world
with discrete digits and signals, perfect and identical components,
etc.

For a discussion of Quantum Computation and Quantum CA, you might find
the article "Parallel Quantum Computation" interesting -- it appeared
in the book "Complexity, Entropy, and the Physics of Information," SFI
Studies in the Sciences of Complexity, Vol. VIII, Ed. W. H. Zurek,
Addison-Wesley 1990.

	Norm Margolus
	MIT Lab for Computer Science
	Cambridge MA