28-03-2005 05:17									#91
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quote: Originally posted by TCO you dropped your hat...

	28-03-2005 05:18									#92
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quote: Originally posted by KrazyHorse No it doesn't.... Trust me, physicists didn't drop the deterministic view without a fight.

What doesn't fit now in stat mech world?

	28-03-2005 05:20									#93
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quote: Originally posted by TCO What doesn't fit now in stat mech world?

Huh? I never said that stat mech doesn't work. I said that the analogy between stat mech and quantum doesn't work.

	28-03-2005 05:24									#94
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GP, I really want to know what you're trying to propose.

I'm saying that the evidence implies that not only do we not know the exact state of a particle at all times but also that the particle does not have an exact state at all times.

If it was merely that we didn't know then particles would not interfere with themselves. The easiest demonstration of them doing so are double-slit experiments (interference between a superposition of position states), but with a bit more effort you can have a particle in a superposition of spin states interfering with itself...

	28-03-2005 05:25									#95
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quote: Originally posted by KrazyHorse No it doesn't.... Trust me, physicists didn't drop the deterministic view without a fight.

I trust you. I just want to understand versus saying I believe based on authority. But I'm lazy. Spoonfeed me.

	28-03-2005 05:25									#96
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quote: Originally posted by KrazyHorse Huh? I never said that stat mech doesn't work. I said that the analogy between stat mech and quantum doesn't work.

so determinism (tree does fall or whatever) does fit with all observations of stat mech?

	28-03-2005 05:33									#97
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quote: Originally posted by TCO I trust you. I just want to understand versus saying I believe based on authority. But I'm lazy. Spoonfeed me.

I already did.

I don't know how many times I can say double slit experiment...

	28-03-2005 05:33									#98
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quote: Originally posted by KrazyHorse GP, I really want to know what you're trying to propose. I'm saying that the evidence implies that not only do we not know the exact state of a particle at all times but also that the particle does not have an exact state at all times. If it was merely that we didn't know then particles would not interfere with themselves. The easiest demonstration of them doing so are double-slit experiments (interference between a superposition of position states), but with a bit more effort you can have a particle in a superposition of spin states interfering with itself...

I'm not PROPOSING anything. Just questioning things. I need to think through your evidence. I need to concentrate to do it. Doesn't come easy.

	28-03-2005 05:34									#99
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quote: Originally posted by KrazyHorse I already did. I don't know how many times I can say double slit experiment...

Like a baby with Gerber is what I want...

Or I just need to break down and exert some effort. That's ok too.

	28-03-2005 05:45									#100
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GP, you have two choices: either the particle is always in a definite state or it is not.

If it is always in a definite state then it has to pass through one or the other slit. It can't be in two places at once. "Wave-particle duality" is just another way of saying that the particle has no definite position (position is an observable, just like any other) therefore it can be described to be in a superposition of position states. If it had a definite position state then the graph of the wavefunction would be a delta spike.

	28-03-2005 05:49									#101
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If it passes through a single slit then each point on the screen has a definite phase factor associated with it since it has to travel a certain distance to get there and the phase is exp(ikr)

however, this means that there are no interference effects (for there to be an interference effect there have to be two impinging waves with different phase factors)

	28-03-2005 05:59									#102
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The thing I dont understand about this thread is:


Is TCO GP?

	28-03-2005 06:00									#103
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< GP |TCO > = 1

	28-03-2005 06:02									#104
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ok kitty. Any experiments related to the actual shroedinger thing that have same effect as slit experiments? I guess I have to buy that the position is not just probabilistic.

	28-03-2005 06:02									#105
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bra ket

	28-03-2005 06:02									#106
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what actual schrodinger thing?

	28-03-2005 06:07									#107
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the cat. Or more broadly speaking the radioactive atom.

	28-03-2005 06:07									#108
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here. take a single electron (S = 1/2) and polarise it in z direction (Sz = 1/2)

Now send it through a beam splitter which sends Sx = 1/2 states to the right and Sx = -1/2 states to the left

Recombine the "beams" of electron (each of which only has a half of the electron in it!) and voila! interference between the two available pathways for a single electron...

edited slightly...

	28-03-2005 06:09									#109
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quote: Originally posted by TCO the cat. Or more broadly speaking the radioactive atom.

Schrodinger's cat is all messed up as a demonstration of quantum principles. It's only really useful as shock treatment to get you used to the fact that things can have indefinite states. It would be almost impossible to decay an atom without performing a measurement on its state.

	28-03-2005 06:17									#110
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quote: Originally posted by KrazyHorse < GP |TCO > = 1

	28-03-2005 10:49									#111
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"Because other choices (for instance what the spin of some other particle in Beijing is) have no effect on the thing being measured...


None whatsoever?


Not if your experiment is done right..."

But how can any experiment, "done right" or not, isolate itself from the tiny but unpredictable influence of mass-bearing objects moving around in the universe? I mean, the gravity of distant stars and other objects must have some very small but measurable and non-isolate-able effect on any particle you are trying to measure.

	28-03-2005 11:07									#112
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They will have some effect on the state of the particle in question, but they will not completely destroy the admixture of states. State superposition is not an all-or nothing thing; it is possible to have the state

(1/2)| 1 > + ((3/4)^(1/2))| 2 >

just as easily as you can have ((1/2)^(1/2)) (| 1 > + | 2 >)

what I'm saying is that if you run the experiment right you will be left very close to an even admixture of | 1 > and | 2 > despite interaction with the outside world (it will jiggle you a bit to one side or the other, but not totally into one state)

	29-03-2005 08:04									#113
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what goes down in stat mech world?

	29-03-2005 08:05									#114
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?

	29-03-2005 08:52									#115
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Do you have an admixture of states?

	29-03-2005 09:10									#116
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You have a number of possible states that a given particle can be in with given probability

Not the same thing. In stat mech it's in one or the other...

	29-03-2005 09:17									#117
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I like that better.

	29-03-2005 09:18									#118
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Do your solved a stat mech problem dance!!!

	29-03-2005 10:00									#120
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good