From: Glenn Morton (glennmorton@entouch.net)
Date: Sun Jul 06 2003 - 20:23:06 EDT
Don Winterstein wrote:
"I've never been terribly interested in this subject, because dealing with
parallel universes seems to be no more than a sophisticated intellectual
game. "
He is in good company with Martin Rees:
"Other universes are not directly observable, but their conceptual status is
on no worse a footing than superstrings (or even the more familiar quarks):
these, too, are unobservable theoretical constructs whose manifestations
help to account for the way the world is.” Martin Rees, Before the
Beginning, p. 173
The interesting thing is that a potential test of MWH has been advocated.
This weekend, I went to the bookstore looking for books on MWH, to learn
more. One of the books I got was Julian Brown, Minds, Machines and the
Multiverse, (new York: Simon & Schuster, 2000). He cites an article by David
Deutsch (which I will order tomorrow). The test is based upon a quantum
computer. Such things are now being built and are in the early stages of
design. See
http://www.usatoday.com/money/industries/technology/2003-06-23-quantum_x.htm
. When venture capitalists start backing a horse, they think it is a real
possibility.
The quantum computer reserves one quantum bit (called a qubit) of its memory
for the test. Normal computers can only have 0's and 1's in the registers.
Quantum computers can have both values at the same time in a single
register. This state is called superposition. The computer puts this memory
location into superposition by performing a logical operation call square
root of NOT. I won't describe that function unless someone really wants the
gory details. The quantum computer (qc for short) observes this memory
register. Under the classic Copenhagen interpretation of physics, this act
of observation will cause the collapse of the superposition yielding a 0 or
a 1 but not both. The odds of a 0 or a 1 are 50-50. According to the
multiverse view of the world, both states continue to exists (this is the
Hugh Everett version of MWH), one in this universe the other in a split off
from ours. Everett's version of MWH claims that every quantum collapse
splits the universe, one universe with one answer the other with the
opposite answer. This is sort of a 'Sliders' type of universe. In one
universe, the machine will see a 0 in the other a 1.
The machine then records that it saw 1 single value in the register but very
importantly, it doesn't record the value. The machine then forgets the
value because if it doesn't forget, the test can't continue. Now, this is
the part of this test of which I am a bit unsure. The next step, after
forgetting the value is to put the state back as it was. I believe this is
the process of quantum erasure. Brown writes:
"Also in recent years, there have been intriguing quantum eraser experiments
in which physicscists have shown that in special circumstances they can
actually undoo the disturbances caused by measurement." p. 90
http://www.bottomlayer.com/bottom/kim-scully/kim-scully-web.htm
I suspect that this forgetting is related to quantum eraser which puts the
system back as it was. Now, another square-root of NOT is applied. Brown
describes it:
"In Deutsch's experiment, interference can be brought about rather simply
by performing another [sqr root] NOT operation on qubit Q, but this time
after the AI machine's observation, What does this do? If the many-universe
interpretation is correct, the superposition Q remains intact during the
observation by the AI machine and the second [sqr root] NOT transforms the
superpositon to the definite state 1. If the Coppehagen intepretation is
correct, however, Q collapses into a definite state of either o or 1 during
the observation, but when the second [sq root] NOT operation is applied,
the qubit is transfored back into a superposition of 0 and 1."
"to complete the experiment, either the computer itself or we, the outside
observers, now measure the state of Q. If many universes is true, we will
see 1 with certaintiy, and if the Copenhagen interpretation is true, we
will see either 0 or 1 at random. To disstinguish between these two outcomes
we would need to repeat the experiment a number of times." Julian Brown
Minds, Machines and the Multiverse, (new York: Simon & Schuster, 2000), p.
349
One other test, which I have alluded to before is illustrated in this
quotation:
"Now imagine how difficult it would be to factor a 250-digit number that
was the product of two large primes. It turns out that even with today's
most advanced supercomputers, it's very unlikely that we would ever be able
to solve such a problem--with the fastest known classical algorithm, it
would take longer than the age of the universe. Yet a quantum computer using
Shor's algorithm, if ever such a machine could be built, could crack the
problem in seconds or minutes because it would be able to compute
simultaneously along as many as 10^5050 or more different pathways. As
Deutsch argues in his book _The Fabric of Reality_, such an unimaginably
large number presents believers in a single universe with a gargantuan
problem:
'There are only about 10^80 atoms in the entire visuble universe, an
utterly minuscule number compared with 10^500.. So if the visible universe
were the extent of physical reality, physical reality would not even
remotely contain the resources required to factorize such a large number.
Who did factorize it, then? How, and where, was the compuation performed?'
"For Deutsch the only answer that makes any sense is that different parts
of the calculation are performed in different universes, all 10^500 of
them. Furthermore, the existence of Shor's algorithm is pwerful testimony
even though it's never actually be run on any hardwar. 'That
argument--'Whwere was it done?--is already valid today even before we have
ever built a factorizatoin engine.' Deutsch said. 'We can look in theory at
the design of the machine, never mind whether we can actually build it. To
me it's no more convincing for somebody to come and tell me, 'Well, look
we've factored this number,' than to look at the equations that say the
machine would factor the number if you could only build it."
"To understand nature in its entirety, Deutsch beleives, we must accept the
existence of an almost limitless number of universes." Julian Brown Minds,
Machines and the Multiverse, (new York: Simon & Schuster, 2000), p.26
If you don't know of Peter Shor's algorithm, then you should do some
research. The software is already in existence to test MWH, Venture
Capitalists are now investing in making quantum computers. Indeed some QCs
have already been built.
http://www.org.chemie.tu-muenchen.de/glaser/qcomp.html
http://www.trnmag.com/Stories/2002/010202/Quantum_demo_does_tricky_computing
_010202.html
My bet is that within 25 years if not sooner, we will have the Deutsch test
run. We christians may hide our head in the sand and ignore what is
happening in computer science with its implications for theology. This is
what we Christians did when the issue of the antipodes was a hot one prior
to when Magellan's cruise proved that people actually did live at the
antipodes. The advances in the next few years may have profoudn theological
implications and we too often think it is an idle game. It isn't.
For a fuller response to Richard's question about what I do. My new job for
my company is to look into the future, see what technology is out there and
get it incorporated prior to when we need it. My new job in the US is no
longer geophysical only. I am the technology research department. It
actually fits what I have been doing with theological issues for many years.
Now I can earn a living doing it.
Glenn Morton
http://home.entouch.net/dmd/dmd.htm
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