Wednesday, January 11, 2012

Bell's paradox

The most divisive issue in physics is Bell's inequality. Some say that it is one of the most profound discoveries in the entire history of science. Others say that it is a trivial observation of no great significance.

No Nobel Prizes have been given for any work related to Bell's inequality, altho a Wolf Prize was given in 2010.

Around 1930, Einstein and others thought that quantum mechanics was wrong, and needed a hidden variable theory. Bohr, John von Neumann, and others convinced everyone that hidden variable theories don't work, and that quantum mechanics is correct. The matter has been settled for 80 years.

In 1964, Bell proposed a way to prove that the hidden variable theories do not work. His plan succeeded, and affirmed what everyone had believed since 1930.

Variants of Bell's argument are published frequently. I mentioned one below.

So all Bell's inequality does is to demonstrate the wrongness of some long-discarded idea. It is like finding a new way to disprove the Plum pudding model of the atom, that was popular from 1904 to 1909. A more recent example is below.

Yet, entire books have been written on why Bell's inequality is so profound. I guess their point is that Bell somehow put his finger on what is strange about quantum mechanics, but it is only in comparison to some other (hidden variable) theory that is just as bizarre as quantum mechanics.

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