Locrian Posted September 1, 2005 Posted September 1, 2005 It is particles which have spin. Yea that's a mistype, thanks for the correction. You have the wrong person listed as the quote though somehow.
5614 Posted September 1, 2005 Posted September 1, 2005 Fixed. Appologies for the mistake, if I violated some kind of copyright rule please don't sue me
J.C.MacSwell Posted September 1, 2005 Posted September 1, 2005 So what is mysterious about that ?I have a stick with one end painted in red and the other painted in blue. I have two box' date=' I close my eyes, break the stick in two and put one piece in each box that I close. I send you one of the box and the other too an other person. When you will open the box and see that you received the blue end. Instantanly you will know that the other received the red end ! HUU fantastic that's magic [/quote'] I think this is an oversimplication (therefore wrong "in theory" although Einstein would have agreed with you). I will offer an oversimplified explanation (therefore probably wrong "in theory" but I will offer it as an analogy and hope someone will correct us both in a way that we can understand): You could have opened the box testing for green vs yellow which is independant of the red vs blue or turquoise vs orange which is partially dependant on the red/blueness and the green/yellowness. By carefully selecting the "colours" of the test you can effect the odds of a subsequent test to the opposite particle even though it had not been "tampered with", at least not locally. Of course it would take a number of particle pair tests to prove this changing of the odds of the opposite particle. I hope the above is perfectly confusing. If not, it is probably "not even wrong" and should be ignored.
Jacques Posted September 1, 2005 Posted September 1, 2005 I hope the above is perfectly confusing. Yes completely confusing. Why test for a color I know will never happen ? The photon are polarised to the left or to the right. If I mesure one to be left, I am sure the other is rigth polarised. I think that the confusion come from the supposition that the photon before mesurement is in both state at the same time (left and rigth polarised) something I don't accept...
5614 Posted September 1, 2005 Posted September 1, 2005 supposition that the photon before mesurement is in both state at the same time (left and rigth polarised) something I don't accept I thought superposition was that it could be either one state or another we say it "posses" both states, but in reality it only has one state, but we don't know it. Schrödinger's cat wasn't dead and alive, it was in an unknown state, represented as saying it was in "both" but something can't be one and the other. When you observe it you find out which state it is in, before that it is in a superposition, we do not know what state it is in.
Jacques Posted September 1, 2005 Posted September 1, 2005 That's what I also think but I think that physicist say superposition is both state at the same time... Can a real physicist give is opinion on that ??
5614 Posted September 1, 2005 Posted September 1, 2005 superposition is both state at the same time It is not literally in both states, a particle cannot have 2 different spins, however we say or refer to it as having both states. A mathematical referrence to something and reality is not always identical. The reason I was picking up on this is because you said "something I don't accept" and I seemed to have made the assumption it was because you don't think e.g. a particle can have an up and a down spin at the same time.
Jacques Posted September 1, 2005 Posted September 1, 2005 That is what I think that we don't know which state it is but it have only one state Thanks for your answers. I was under the impression that physicist where realy thinking that it was in the 2 state at the same time. I think that some physicist mixup reality and mathematic
J.C.MacSwell Posted September 1, 2005 Posted September 1, 2005 I thought superposition was that it could be either one state or another we say it "posses" both states' date=' but in reality it only has one state, but we don't know it.[/b']Schrödinger's cat wasn't dead and alive, it was in an unknown state, represented as saying it was in "both" but something can't be one and the other. When you observe it you find out which state it is in, before that it is in a superposition, we do not know what state it is in. I think this interpretation has been consistently on the losing end of the argument for the last 70 years, at least in the eyes of most physicists.
J.C.MacSwell Posted September 1, 2005 Posted September 1, 2005 Yes completely confusing. Why test for a color I know will never happen ? The photon are polarised to the left or to the right. If I mesure one to be left, I am sure the other is rigth polarised[/b']. I think that the confusion come from the supposition that the photon before mesurement is in both state at the same time (left and rigth polarised) something I don't accept... But don't you have to choose an axis about which to test the polarisation? Are you not "forcing" a 100% left or 100% right choice on the photon?
Locrian Posted September 2, 2005 Posted September 2, 2005 I thought superposition was that it could be either one state or another we say it "posses" both states, but in reality it only has one state, but we don't know it. No, that's exactly what superposition doesn't say. Superposition states that a state function is made up of a linear combination of all (orthonormal) eigenstates. It does not say it is one eigenstate and you don't know which.
swansont Posted September 2, 2005 Posted September 2, 2005 I think this is an oversimplication (therefore wrong "in theory" although Einstein would have agreed with you). I will offer an oversimplified explanation (therefore probably wrong "in theory" but I will offer it as an analogy and hope someone will correct us both in a way that we can understand): You could have opened the box testing for green vs yellow which is independant of the red vs blue or turquoise vs orange which is partially dependant on the red/blueness and the green/yellowness. By carefully selecting the "colours" of the test you can effect the odds of a subsequent test to the opposite particle even though it had not been "tampered with"' date=' at least not locally. Of course it would take a number of particle pair tests to prove this changing of the odds of the opposite particle. I hope the above is perfectly confusing. If not, it is probably "not even wrong" and should be ignored. [/quote'] That's basically right. The limitation of saying the two photons will always have orthogonal polarizations is that you have neglected to say how you measure it: you have to choose an axis to be | vs ---. So while you know the other photon's polarization instantly, you can't communicate how you measured it to anyone else faster than c, to give them access to the same information.
swansont Posted September 2, 2005 Posted September 2, 2005 I think this interpretation has been consistently on the losing end of the argument for the last 70 years, at least in the eyes of most physicists. Yes. The Bell's Inequality measurements point toward there not being local hidden variables.
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