03 Dec '10 12:48>
Originally posted by black beetleWhy would existence require localization?
If a particle is not localized to a specific point in spacetime, how can you claim that it is existent?
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Originally posted by KazetNagorraI am not using "ancient texts" (records of human thought) as proof, I am indicating the logical and substantial metaphysical attempt within them at interpretation of the phenomenon, and their remarkable coherence with modern scientific findings.
Particles are always both localized and a wave, neither of the descriptions, in their pure form, make any sense in a quantum mechanical way. A (pure) wave cannot be normalized and (pure) localization is not a function (it's a so-called generalized distribution, a delta function).
I don't see any value in "ancient texts" as long as they cannot be used in any predictive way. Ad hoc interpretations don't impress me.
Originally posted by KazetNagorraThe state of the particle -its temporal behavior- is changing constantly as a result of the constant change of the measured system. Therefore, we would rather talk about the specific (constant, until it is altered by outside intervention) orbit of the particle instead of giving its actual permanently changing coordinates. It is clear that the state of the system will change solely in the case of the occurrence of an interaction with another system.
Particles exist (why describe something that you're not sure, or at least assuming, exists?), they are just not localized to a specific point in spacetime, nor can you describe them using a wave with a single wavelength.
Originally posted by black beetleNot necessarily, this depends on the potential. But there is also no reason why the potential cannot depend on time explicitly in which case it is almost always not true that the square of the wavefunction is constant in time.
Since a trapped undisturbed quantum particle lacks of a defined location, the probability to measure the particle at a certain location remains constant over time
Originally posted by KazetNagorraStill, the probability to measure at a certain location an undisturbed entrapped quantum particle remains constant over time but changes throughout space. A constant probability distribution is typical for particles trapped in a constant potential well, as is the case of an electron in the electric field of a proton
Not necessarily, this depends on the potential. But there is also no reason why the potential cannot depend on time explicitly in which case it is almost always not true that the square of the wavefunction is constant in time.
Originally posted by black beetleBut in a real situation, the potential term will always depend on time, so what are you trying to argue here? Also, I'm not sure that even in the hydrogen atom case, which can be solved analytically, you still get a constant potential if you allow for motion of the proton due to the electron (in the textbook example, the proton is assumed to be stationary due to its much larger mass). Without the assumption you can no longer calculate the solution analytically.
Still, the probability to measure at a certain location an undisturbed entrapped quantum particle remains constant over time but changes throughout space. A constant probability distribution is typical for particles trapped in a constant potential well, as is the case of an electron in the electric field of a proton
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Originally posted by KazetNagorraI argue that I explained you in detaild the reason why the tetrallema I mentioned earlier holds, and your reply was that you reject the idea that the probability to measure the entrapped undisturbed in a 3D well particle at a certain location remains constant over time but changes throughout space; so I clarified I was talking about the particle location and the time dependency of the wavefunction in the context of the wave mechanics -and I remind you that we are also talking about the nature of the particle
But in a real situation, the potential term will always depend on time, so what are you trying to argue here? Also, I'm not sure that even in the hydrogen atom case, which can be solved analytically, you still get a constant potential if you allow for motion of the proton due to the electron (in the textbook example, the proton is assumed to be stationa ...[text shortened]... uch larger mass). Without the assumption you can no longer calculate the solution analytically.
Originally posted by black beetleI don't get what you mean, in general the probability density is not constant in time at all, and there are only a few mathematically idealized situations where it does hold. There is no "particle location" apart from the wavefunction being localized around some expectation value. You should not (in my opinion) interpret the wavefunction after measurement as revealing where the particle was prior to measurement; if I'm not mistaken such an interpretation would be in violation of Bell's theorem.
I argue that I explained you in detaild the reason why the tetrallema I mentioned earlier holds, and your reply was that you reject the idea that the probability to measure the entrapped undisturbed in a 3D well particle at a certain location remains constant over time but changes throughout space; so I clarified I was talking about the particle locatio ...[text shortened]... e wave mechanics -and I remind you that we are also talking about the nature of the particle
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Originally posted by KazetNagorraThis simply means that the particles are neither existent, nor not existent, nor both existent and non existent, nor neither
I don't get what you mean, in general the probability density is not constant in time at all, and there are only a few mathematically idealized situations where it does hold. There is no "particle location" apart from the wavefunction being localized around some expectation value. You should not (in my opinion) interpret the wavefunction after measureme ...[text shortened]... rement; if I'm not mistaken such an interpretation would be in violation of Bell's theorem.
Originally posted by KazetNagorraEdit: "You should not (in my opinion) interpret the wavefunction after measurement as revealing where the particle was prior to measurement;"
I don't get what you mean, in general the probability density is not constant in time at all, and there are only a few mathematically idealized situations where it does hold. There is no "particle location" apart from the wavefunction being localized around some expectation value. You should not (in my opinion) interpret the wavefunction after measureme ...[text shortened]... rement; if I'm not mistaken such an interpretation would be in violation of Bell's theorem.