Re: Quantum Computers

From: Anders Sandberg (asa@nada.kth.se)
Date: Tue Aug 24 1999 - 06:54:23 MDT


jmcasey@pacific.net.sg writes:

> I hear what you're saying, but...
>
> >Heisenberg tells us that there is a point where the change to a physical system
> >is so small that there is no change at all.
>
> ...surely this challenges the concept of emergence? I'm imagining
>the subatomic equivalent of the butterfly in Beijing "causing" the
>thunderstorm in Toronto. Are *all* the changes which are so small as
>to "be" no change at all, still no change in aggregate? (If not, of
>course, they were never really *no* change.)

Actually, all the tiny quantum fluctuations together do have emergent
and noticeable effects. Heisenberg only showed that measurement
uncertainties will always be larger than a certain level, essentially
placing a limit on how well we (or anything else) can distinguish
quantum states. Even tiny quantum noise that cannot be detected itself
can add together to create "macro" effects such as coupling constants
and shielding of electron charges (if I remember my Feynmann lectures
right).

-- 
-----------------------------------------------------------------------
Anders Sandberg                                      Towards Ascension!
asa@nada.kth.se                            http://www.nada.kth.se/~asa/
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