Question regarding the three polarizer paradox

[sophiecentaur]

Well, it's always more fun to solve a straightforward problem when it is presented as a "paradox". At least to me.

That's probably true. It can bring out your argumentative side and makes you more determined to disprove the paradox. Everyone loves a Devil's Advocate.

 

[Andy Resnick]

Can it be explained classically?

Yes, using Jones vectors. The 3-polarizer setup is a very useful (and classical) way to demonstrate the behavior of spin-polarized atoms in magnetic fields. The Pauli spin matrices serve double-duty as Hermitian polarization operators.

The central concept common to both is 'change of basis states'.