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sharnrock
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Neither one. The NPR note is a very unfortunate use of the term "shape". The experiment they're talking about is an attempt to measure the electron's electric dipole moment. A nonzero electric dipole moment would not imply that the electron has a finite size.sharnrock said:
Drakkith said:An electron is a quantum object that obeys both wavelike and particle-like rules.
It's both. It's neither. Nobody knows exactly.electron...wave or particle?
“Do not keep saying to yourself, if you can possible avoid it, "But how can it be like that?" because you will go 'down the drain', into a blind alley from which nobody has escaped. Nobody knows how it can be like that.
UltrafastPED said:The "wave-particle duality" behavior of electrons can be observed during any electron diffraction experiment:
Naty1 said:Richard Feynman says something like "Everything you need to know about QM can be gleaned from the double slit experiment.."Of course, he was a genius... and also had other conflicting comments about QM:
...In QM a quantum particle is neither particle or wave
These probability calculations require a state vector {ket ψ} , which is determined by the preparation procedure.
...In this presentation, the Born postulate is used to obtain the interference pattern for
particles scattered from a system of slits without referring, a priori, to classical wave
theory
In his 1926 paper,[10] Max Born suggested that the wave function of Schrödinger's wave equation represents the probability density of finding a particle...
..Either we do physics on a large scale, in which case we use classical level physics; the equations of Newton, Maxwell or Einstein and these equations are deterministic, time symmetric and local. Or we may do quantum theory, if we are looking at small things; then we tend to use a different framework where time evolution is described... by what is called unitary evolution...which in one of the most familiar descriptions is the evolution according to the Schrodinger equation: deterministic, time symmetric and local. These are exactly the same words I used to describe classical physics.
However this is not the entire story... In addition we require what is called the "reduction of the state vector" or "collapse" of the wave function to describe the procedure that is adopted when an effect is magnified from the quantum to the classical level...quantum state reduction is non deterministic, time-asymmetric and non local...The way we do quantum mechanics is to adopt a strange procedure which always seems to work...the superposition of alternative probabilities involving w, z, complex numbers...an essential ingredient of the Schrodinger equation. When you magnify to the classical level you take the squared modulii (of w, z) and these do give you the alternative probabilities of the two alternatives to happen...it is a completely different process from the quantum (realm) where the complex numbers w and z remain as constants "just sitting there"...in fact the key to keeping them sitting there is quantum linearity...
QUOTE]
Does Marcella's approach offer any 'better' insights??
Naty1 said:Do you think Feynman's comment was before 'the full machinery' of QM was available?
Naty1 said:I'd be interested in your views on some points in Marcella's paper
Naty1 said:So is Marcella dismissing the prior scientists view that he mentions...Ballentine, Merzbacher...etc..if so what is ψ in HIS world view...
Naty1 said:Born postulate? I thought that postulate was 'old hat'...Seems like waves are there in relatively plain sight whether he wants to acknolwedge them or not...
Naty1 said:Or does Marcella mean something different do you think...??
Naty1 said:So far I'm not understanding why you like this paper in preference to the older Schrodinger view
Naty1 said:So do these particular formalisms lead to some additional insights in the the 'full quantum formalism' you mean?
Naty1 said:In addition we require what is called the "reduction of the state vector" or "collapse" of the wave function to describe the procedure that is adopted when an effect is magnified from the quantum to the classical level...quantum state reduction is non deterministic, time-asymmetric and non local
... so guess what - one can associate states with a preparation procedure. This is the most modern view and is what Ballentine gives in his book.
I could not glean anything really 'new' or more 'correct' from that paper because apparently I was already pretty much 'up to date' from discussions in these forums.That way of analysing it is a leftover from pre QM days - here is the correct QM analysis:
http://arxiv.org/ftp/quant-ph/papers/0703/0703126.pdf
bhobba said:That's just one reason why IMHO textbooks should not be based on rehashing the historical development, but rather develop it from its conceptual core. Ballentine - QM - A Modern Development does it this way and books like this should be the goal of everyone interested in QM to dispel leftover myths from other approaches.
BTW I am pretty sure Ultrafast is basically saying the same as me - just a bit differently and is simply meant to compliment what he said.
Naty1 said:I could not glean anything really 'new' or more 'correct' from that paper because apparently I was already pretty much 'up to date' from discussions in these forums.
UltrafastPED said:Just so long as they don't forget to connect things to experiments!
I agree ... it would sure be nice if people would record their educational level in their individual profile!Dadface said:I think this thread illustrates an apparent problem with the way that many threads progress on this forum.The problem is that I suspect that many of the responses here are at a level which does not take into account the present educational level of sharnock.
Naty1 said:I started out in these forums with no formal education in quantum mechanics...explanations over my head were pretty common at first but became less so as I learned more from experts here. So I took notes [copied and pasted what I thought were interesting posts] and have accumulated several hundred pages on QM.
Sharnock has the same choice we all do:
"Too complicated, I give up." or
"Wow, really interesting, I'll study that more."
An electron is a fundamental particle that makes up the building blocks of matter. It has properties of both a wave and a particle, known as wave-particle duality.
This phenomenon is explained by the principles of quantum mechanics. Electrons can exhibit wave-like behavior, such as interference and diffraction, but also have discrete properties like mass and charge.
The double-slit experiment is a classic example that shows how electrons can behave like waves. This experiment involves firing electrons through a barrier with two slits, and observing an interference pattern on a screen behind the barrier.
No, the act of observation or measurement forces the electron to behave either as a wave or a particle, but not both simultaneously. This is known as the observer effect.
The wave-particle duality of electrons challenges our traditional understanding of the physical world and highlights the limitations of classical physics. It has led to the development of quantum mechanics, which has revolutionized our understanding of the behavior of particles at the atomic and subatomic level.