Re: Which universe are we in? (tossing tennis balls into spinning props)
On n Tuesday, July 16, 2002, at 11:02 Tim May wrote:
On Tuesday, July 16, 2002, at 10:39 AM, Peter Fairbrother wrote:
Oh dear. QM does rule out internal states. I didn't think I would
have to explain why I capitalised Bell, but perhaps it was a bit
too subtle. Google Bell and inequalities, and go from there.
I disagree. Bell's Inequality is not dependent on QM...it's a
mathematical statement about the outcomes of measurements where
stochastic processes play a role. The fact that QM is strongly
believed to involve stochastic processes is why Bell's inequality
shows up prominently in QM. However, we cannot then use B.I. to
prove things about QM.
It's a statement about quantum mechanics. Quantum mechanics and the
violation of bell's inequality rest on the inseparability of a quantum
state. Typically, that means a test using an epr pair, i.e. a pair of
S = 1 photons with total J = 0, so that the pair behaves as a single
object with J = 0. The pair MUST be originate from the same quantum
process, (e.g., a single \pi_{0} decay), not as two arbitrarily selected
photons from a stochastic process (e.g., 2 photons selected at random
from the 4 produced in the decay of two pions). In short, quantum mechanics
is not stat mech.
A more persuasive proof of why hidden variables are not viable in QM is
the work done on extending some theorems about Hilbert spaces. Namely,
Gleason's theorem from the mid-50s, later extended by Kochen and Specker
in the 1960s. The Kochen-Specker Theorem is accepted as the no go
proof that hidden variables is not viable.
While K-S is an improvement, it's fundamentally the same idea as bell's
but eliminates a loop-hole:
From: http://plato.stanford.edu/entries/kochen-specker/
This is the easiest argument against the possibility of an HV
interpretation afforded by Gleason's theorem. Bell (1966: 6-8) offers a
variant with a particular twist which later is repeated as the crucial
step in the KS theorem. (This explains why some authors (like Mermin
1990b) call the KS theorem the Bell-Kochen-Specker theorem; they think
that the decisive idea of the KS theorem is due to Bell.[3]) He proves
that the mapping dictates that two vectors and mapped into 1 and 0
cannot be arbitrarily close, but must have a minimal angular separation,
while the HV mapping, on the other hand, requires that they must be
arbitrarily close.
In any case, quantum mechanics is well established by a lot of convincing
arguments, even without any of the above to rely upon.
Re: Which universe are we in? (tossing tennis balls into spinning props)
At 03:27 PM 7/15/02 +0100, Peter Fairbrother wrote: Optimizzin Al-gorithym wrote: And while QM can't help you with a particular atom, it also doesn't say that its impossible that knowledge of internal states of the atom wouldn't help you predict its fragmentation. Yes it does. Heisenberg Uncertainty Principle. Ring a Bell? The uncertainty principle says that there is a limit on the information about position and change in position that you can collect. It does not rule out internal states. For instance, you could generate particles with a certain property which you do not have to measure to know that they have that property. It is a logical mistake to think that because you can't see it in 2002, you can't ever measure it, or it doesn't exist. When something appears 'random', it is because of (wholly normal) ignorance on our part. Sometimes 'randomness' is used to shut off analytic machinery, much like 'God' (this latter idea is Minsky's).
Re: Which universe are we in? (tossing tennis balls into spinning props)
On Tuesday, July 16, 2002, at 10:39 AM, Peter Fairbrother wrote: Oh dear. QM does rule out internal states. I didn't think I would have to explain why I capitalised Bell, but perhaps it was a bit too subtle. Google Bell and inequalities, and go from there. I disagree. Bell's Inequality is not dependent on QM...it's a mathematical statement about the outcomes of measurements where stochastic processes play a role. The fact that QM is strongly believed to involve stochastic processes is why Bell's inequality shows up prominently in QM. However, we cannot then use B.I. to prove things about QM. A more persuasive proof of why hidden variables are not viable in QM is the work done on extending some theorems about Hilbert spaces. Namely, Gleason's theorem from the mid-50s, later extended by Kochen and Specker in the 1960s. The Kochen-Specker Theorem is accepted as the no go proof that hidden variables is not viable. The uncertainty principle was generally considered to rule out internal states long before Bell, though. Since around 1930, I think. Whether QM/the uncertainty principle is wrong is a different question. Until K-S and related proofs, Bohm's internal states model (hidden variables) was not considered to be ruled out. I recommend a recent book, Interpreting the Quantum World, by Jeffrey Bub, 1997. He summarizes the various interpretations of quantum reality and explains the K-S theorem reasonably well. The Asher Peres book on QM is also good. But, as I said, I accidentally beamed the message into this world. Those interested in discussing quantum reality and things like that should look into lists oriented in this direction. I don't think most list members here have the interest or the background, so discussions would be swamped by failures to communicate, abuses of language, and tangent rays. --Tim May They played all kinds of games, kept the House in session all night, and it was a very complicated bill. Maybe a handful of staffers actually read it, but the bill definitely was not available to members before the vote. --Rep. Ron Paul, TX, on how few Congresscritters saw the USA-PATRIOT Bill before voting overwhelmingly to impose a police state
Re: Which universe are we in? (tossing tennis balls into spinning props)
On Mon, 15 Jul 2002, Major Variola (ret) wrote: The uncertainty principle says that there is a limit on the information about position and change in position that you can collect. It does not rule out internal states. Yes it does, it says that any time you measure a system it WILL be in an unknown state after the measurement. No if's, no but's. It effects photons (which I challenge you to demonstrate has 'charge') as well as electrons and protons. It's universal. It's about measuring, not about what is being measured. The 2nd also comes into play because any mechanism you use to 'manipulate' that internal state must also effect that state in a negative way. You're screwed two ways from Sunday. -- When I die, I would like to be born again as me. Hugh Hefner [EMAIL PROTECTED] www.ssz.com [EMAIL PROTECTED] www.open-forge.org
Re: Which universe are we in? (tossing tennis balls into spinning props)
At 03:21 PM 7/14/02 +0100, Ben Laurie wrote: Eric Cordian wrote: Still, Nature abhors overcomplexification, and plain old quantum mechanics works just fine for predicting the results of experiments. Oh yeah? So predict when this radioactive isotope will decay, if you please. You mean this particular *atom* will decay. And while QM can't help you with a particular atom, it also doesn't say that its impossible that knowledge of internal states of the atom wouldn't help you predict its fragmentation. Think about tossing tennis balls through spinning propellers. You might think you could only characterize the translucent prop-disk by a certain probability that the ball would get through vs. get shredded. (Propeller mechanics) But if you could see the phase of the prop as it spun, you could time your tosses and predict which would get shredded. But without that high-speed strobe, you just think there's a disk where there's really a spinning blade.
