Re: Is Quantum Teleportation possible

Dear Ryan,

You have a very interesting question and you have clearly read a little
into the subject, but from your question I think you are in a bit of a
muddle.

I think we should divide the answer into two categories... that which has
been tested currently and that which is just theory. I think I will do this
in reverse order.

Firstly, that which is pure theory... On the subject of Quantum Foam (which
I have to say, however, that I don't know a great deal about) - there is a
lot of theoretical effort being put into this at the moment, but to my
knowledge there is noone trying to test this theory directly. The theories
on how the Universe is constructed are just that, theories. One day,
hopefully, we will be able to construct some test, but until then the
high-flying theoreticians will have to just use what knowledge we already
have from studying the stars and from particle physics where particles are
fired at each other and the bits and peices that fly off, examined. I don't
have a good reference for this but maybe a good place to start would be
CERN's web site: http://public.web.cern.ch/Public/
which will tell you a
little bit about particle physics and about the most advanced experiments
that are being performed to determine how the universe works.

On the subject of multi-universes or "The many-worlds interpretation of
quantum mechanics" - this is a theory which has been popularised by David
Deutsch (http://www.qubit.org/people/david/David.html) who believes that
the best way to describe physics is in terms of an infinite number of
interacting universes. This has never actually been successfully tested
(and some would say that it is impossible to test). Some physicists believe
in his theories, some definitely do not and some are undecided. I am
undecided since I don't think we have any evidence for or against (yet).
However, you don't actually need multiple universes for teleportation and
the way that multiple universes would enter into our theoretical
understanding, were they required, would not actually change how things
work. If you are still interested in multiple-universes then I am afraid
there is nothing for it, but to do a lot of reading because the arguments
are quite drawn out, but very subtle. Here books such as John Gribbon's "In
Search of Schrodinger's Cat : Quantum Physics and Reality" would be a good
start then you could probably start to read some of Deutsch's books.
 http://www.amazon.com/exec/obidos/ASIN/0553342533/qid=1017168084/sr=2-1/ref=sr_2_1/103-2171354-1305453

Now to reality... What can be done with teleportation? I think a better
question might be, "What do physicists consider teleportation to be at the
moment?". The point, you see, is that so far the only thing that has been
teleported is (at most) one particle. By one particle I mean a particle of
light (a photon) or a particle of matter (an atom). And, would you believe,
not even this... the particle itself did not move! The thing that is really
teleported is the information about the particle. In all experiments of
this type you need two particles to start off with. A basic description is
that particle A is marked in some way and B is not. Then after some
interaction B has the markings that A had, but B now is unmarked. Hence the
information is teleported from A to B. Sadly this is the state of the art.

Now, there are those who say that physics is just information so, if we can
teleport information, we can also teleport real things. However, since it
is really really hard to teleport the information from one particle it
would be almost impossibly difficult to teleport even the simplest
biological molecule such as a protein or virus. Plus you would need two to
start off with. A fairly light-hearted discussion on this is given by
Samuel Braustein at  http://www.sees.bangor.ac.uk/~schmuel/tport.html

As for companies keeping it quiet, I don't think this is the case. In fact,
from our own work on the subject, we are constantly giving seminars and
talking to the press about it to try to get the public interested. Also
there is a lot of material readily available on the web:

IBM has a research group on this: http://www.research.ibm.com/quantuminfo/

Caltech are working on it: http://www.cco.caltech.edu/~qoptics/

A world leader in this is Anton Zeilinger in Vienna: http://www.quantum.univie.ac.at/

Also Los Alamos research labs have not been keeping quiet about their work
by Richard Hugues (of course their search engine is down when I write this)
but you can check it out (hopefully) at http://www.lanl.gov

There is also work by the British Defence Research Agency (DRA) now called
QinetiQ: (not that they have anything on their web site currently)
 http://www.qinetiq.com/index_flash.asp

So, sadly, teleportation is not as advanced as you might hope but we will
keep working on it! I hope this answers some of your questions.

Best wishes,

Phil.

---

Dr. Phil Marsden
--------------------------------------------------------------------------
Department of Microelectronics and Information Technology
Laboratory of Quantum Electronics and Quantum Optics
Royal Institute of Technology (KTH) Stockholm
Electrum 229
Street address for Courier deliveries: Isafjordsgatan 22
SE-164 40 Kista, SWEDEN
Tel: +46-8-752 11 89               Fax: +46-8-752 12 40
Mobile: +46-73-957 04 62
Email: phil.marsden@physics.org or phil.marsden@ieee.org
Web: http://www.ele.kth.se/~phil
--------------------------------------------------------------------------