From: Smigrodzki, Rafal (SmigrodzkiR@msx.upmc.edu)
Date: Mon May 20 2002 - 11:59:26 MDT
Michael Roy Ames [mailto:email@example.com]
----- Original Message -----
From: Smigrodzki, Rafal <SmigrodzkiR@msx.upmc.edu>
> The recent factorization of the number 15 by a quantum
> mechanical algorithm makes the existence of the other
branches of reality
> increasingly difficult to ignore.
Hold the phone! Inference error! The existence of Quantum
theory, and its practical application to quantum computing,
does not infer
the truth or falsehood of the Multiverse POV. AFAIK the
Multiverse POV has
provided no additional predictions over those given by QM.
I haven't heard
of even a single test that might prove the M-POV true, or
false, or even
change the likelihood of it at all. (Or have I missed
### Well, not being a physicist, my answer might be vague
but here it goes: MV does say that when a superposition decoheres, all
eigenstates achieve independent existence, while a classical QM, only one
eigenstate is real - the one containing the observer. Now, if you ask what
is means to be real, a metaphysical question, both physicists and
philosophers will have difficulty with a clear answer. Some, like David
Bohm, will say that our universe is real but there is also a "guiding wave",
equivalent to all the other branches of the universe, yet somewhat less
real. Others will flatly refuse an answer, like the Copenhagen school
On a bit more naive level, we tend to think that a correct
mathematical answer can be only provided by a really existing computer, not
an imaginary device. Therefore, if you successfully use a computer whose
functioning depends on a superposition of states, not on a single
eigenstate, you would have to conclude that all the eigenstates have an
existence, at least enough to perform calculations. This would become even
more striking once the machine operates on a few hundred qubits, equivalent
to 10x80 atoms (give or take a couple orders of magnitude), in effect
outperforming a classical Turing machine the size of the visible universe.
You need real particles to make a real factorization. So, I claim that
calculation is proof of existence of the device performing the calculation.
This is somewhat similar to the philosophy of Henri Bergson, who entertained
the idea that physics is a branch of mathematics, and there is no absolute
difference between the existence of a mathematical or a physical object.
Now, if we ever build a quantum computer capable of passing
the Turing test, with significant parts of its reasoning implemented in the
superposition, it would also constitute proof that the other branches of the
multiverse may contain conscious (i.e. Turing-capable) entities.
If the "other" particles in a superposition can calculate,
and even consciously think, then we'd have to conclude they are real. By
extension, it would be then somewhat artificial to think that *only* the
superposition of a small region of the universe (the quantum computer) has a
multiplicity of really existing eigenstates - you would have to seriously
consider the idea that the whole universe is a superposition of real
eigenstates - a multiverse.
The MV theory does not contradict classical QM, but it does
predict that quantum computers will provide real mathematical answers (even
ones unattainable using all the known matter in our universe), and might
even be able to provide a narrative (as an observer) describing quantum
states in a superposition, an idea rather difficult to reconcile with the
I sincerely hope that Quantum Computing proves-out its early
could put an additional exponent of 'more' into Moore's Law.
If it proves
practical, then you can bet the year QC kicks in will see an
not a doubling,
but a 256-fold increase in computing power, partly because
problems will be completely side-stepped by QC chips.
### Yes, yes, yes!
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