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Gweg

Confusing quantum physics is confusing

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http://www.scienceda...20116095529.htm

I think i pretty well understand the gist of it but its kind of impossible to wrap your head around.

It is always impossible to wrap your head around gimmicky explanations of abstract physics concepts that can probably only really be understood by studying quantum mechanics for some time and dealing with all the math that it requires. Even worse, writers often try to explain the uncertainty principle (which is a purely quantum mechanical phenomenon) in terms of classical physics descriptions of a higher energy photon "kicking" the electron more. There's no possible way to understand the uncertainty principle in terms of a classical conception of colliding billiard-balls or anything like that. It's something that can only be explained by deriving it from the fundamental mathematics of quantum mechanics.

The original argument for the uncertainty principle by Heisenberg was based on a somewhat classical imagining of a photon and electron collision. This link, using only algebra and some diffraction concepts, explains Heisenberg's original argument:

http://www.aip.org/h...enberg/p08b.htm

However at the end they offer this warning:

Looking closer at this picture, modern physicists warn that it only hides an imaginary classical mechanical interaction one step deeper, in the collision between the photon and the electron. In fact Heisenberg's microscope, although it was a big help in developing and teaching the quantum theory, is not itself part of current understanding. The true quantum interaction, and the true uncertainty associated with it, cannot be demonstrated with any kind of picture that looks like everyday colliding objects. To get the actual result you must work through the formal mathematics that calculates probabilities for abstract quantum states. Clever experiments on such interactions are still being done today. So far the experiments all confirm Heisenberg's conviction that there is no "real" microscopic classical collision at the bottom.

It appears that the Nature article is arguing about subtleties of applying the uncertainty principle to measurements, and the importance of considering the quantum nature of the detector as well, rather than the semi-classical/semi-quantum Heisenberg-like argument that is often invoked.

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