# Physics for beginners/17-quantum interpretations

## Notes

Even with antireflective coating, some light is reflected off a glass surface. The wave equation for light and sound correctly model such partial reflections. Schrödinger's wave equation calculates molecular and atomic energy levels with very high precision. So if this same wave equation predicts predict partial reflection, we would expect these (almost) "indivisible" elementary particles to somehow go in two different directions at the same time.

A wavepacket sriking a barrier will be split into two parts. At the moderate energies associated with chemistry, electrons never "split" in the sense that new particles are not created. There is only one property of an "indivisible" object that can be in two places at once: That property is probability.

There seems to be only one way to reconcile a wave that so successfully models how light (and radio waves) interact with the atom with the fact that this wave so easily travels in many directions:

The wavefunction must describe where the particle might be!

## Bell's theorem and quantum entanglement

The system described above involves one particle that can be in one of two different places. To model the paradoxical behavior associated with Bell's theorem we require a bit more complexity. First, we need wave that not only can be in two different places, it needs to wave in two different directions.

Shown to the right is one of two degenerate standing waves that can occur if the wave is confined to lie within a circle. Both waves are commonly called 2p states. The other 2p state is oriented perpendicular to the one shown in the figure.

We also need two different particles, depicted here as coffee and tea, located in two cups that can moved apart so that they are separated by vast distances. By tradition, the two cups in a Bell's theorem experiment are called Alice and Bob. And given the analogy to sloshing liquids, it is not unreasonable to call the two particles Coffee and Tea. We don't know which beverage is in which cup. But we do know that if one is in Alice, the other is in Bob. And we know something about how the beverages are sloshing. For example, if one is sloshing in the clockwise direction, the other is counterclockwise.

For more details on this analogy, visit WikiJournal_of_Science/A_card_game_for_Bell's_theorem_and_its_loopholes/Tube_entanglement.

For a collection of quizzes on this subject visit Quizbank/Bell.

All pages associated with this WikiJoural article are listed at Special:PrefixIndex/WikiJournal_of_Science/A_card_game_for_Bell's_theorem_and_its_loopholes

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Each subpage is devoted to a chapter of Matthew Raspanti's original work. Click the image of the pdf file shown to the right to read the chapter.