On 13 Dec 2012, at 04:39, meekerdb wrote:
On 12/12/2012 4:01 PM, Jason Resch wrote:
On Wed, Dec 12, 2012 at 5:15 PM, meekerdb <meeke...@verizon.net>
wrote:
On 12/12/2012 9:25 AM, John Clark wrote:
On Tue, Dec 11, 2012 meekerdb <meeke...@verizon.net> wrote:
On 12/11/2012 9:31 AM, Jason Resch wrote:
>>> Everett's QM is not a theory; it's just an interpretations.
>> Not quite. Deutsch's proposed experiment with reversible
computation and an AI yields different results for the CI and
MWI, thus they are theories which can be tested and differentiated.
> Except his proposed experiment relies on a hypothetical quantum
computer that is conscious.
Yes but Deutsch argues, convincingly I thought, that the reason
it's so difficult to test is not the Many World's theory's fault,
the reason is that the conventional view says that conscious
observers obey different laws of physics, Many Worlds says they do
not, so to test who's right we need a mind that
uses quantum properties.
In Deutsch's experiment to prove or disprove the existence of many
worlds other than this one a conscious quantum computer shoots
electrons at a metal plate that has 2 small slits in it. It does
this one at a time. The quantum computer has detectors near each
slit so it knows which slit the various electrons went through.
The quantum mind now signs a document saying that it has observed
each and every electron and knows what slit each electron went
through. It is very important that the document does not say which
slit the electrons went through, it only says that they went
through one slit only, and the mind has knowledge of which one.
Now the mind uses quantum erasure to completely destroy the memory
of what slits the electrons went through. But all other memories
and the document remains undamaged.
But why should I think this is possible? I'd like to see the
actual mechanism or Hamiltonian that allows this.
And then the electrons continue on their way and hit the
photographic plate. Now develop the photographic plate and look at
it, if you see interference bands then the many world
interpretation is correct.
No, it only means the 'consciousness collapses the wave-function'
theory is incorrect. It doesn't follow that MWI is correct.
If observing a definite result doesn't collapse the wave function
then what does?
Creating a record of it.
I think the experiment is meant to show collapse does not happen.
And if there is no collapse then you have the MWI.
MWI has the same problem as decoherence theory (except it tries to
ignore it): How or what chooses the basis in which the reduced
density matrix becomes approximately orthogonal and what is the
significance of it not being exact. Copenhagen said the choice is
made by the experimenter and apparently Deutsch agrees with this
because he thinks it's significant that his AI is conscious.
Decoherence theory hopes to show it is some objective feature of the
experiment, e.g. the Schmidt decomposition and purification has been
proposed
http://ipg.epfl.ch/lib/exe/fetch.php?media=en:courses:2009-2010:qit:lect5quantinfo0910.pdf
Neither has really said how to deal with the inexactness of
orthogonality, but once you assume you can ignore the off diagonal
terms then QM just predicts probabilities, as Omnes says.
That works FAPP.
But there is no conceptual reason to ignore the off diagonal terms,
given that they can play role physically testable. It is
instrumentalist.
If you define a world by the transitive closure of interactions, then
the linearity of the SWE and the linearity of the tensor product
entails the existence of the many worlds. The many worlds is just the
literal reading of QM applied to our world including us.
And I think QM itself, the wave, is already a literal reading of
arithmetic by itself, ... but I can't convince people who believes in
Something or Someone selecting their realities and not the others.
Bruno
http://iridia.ulb.ac.be/~marchal/
--
You received this message because you are subscribed to the Google Groups
"Everything List" group.
To post to this group, send email to everything-list@googlegroups.com.
To unsubscribe from this group, send email to
everything-list+unsubscr...@googlegroups.com.
For more options, visit this group at
http://groups.google.com/group/everything-list?hl=en.
