Copenhagen v Decoherence

Bohr, Heisenberg, and Pauli

The Measurement problem in quantum mechanics is indeed a problem, but Neil Bates and I have a Copenhagen-ish attitude re interpretations of QM: mainly don't worry about things you can't test or know ... yet.

I don't particularly like weak-ish Copenhagen, let's just say I find it the least distasteful of QI, and of course it is very weak, very general, like that most general of equations, Wheeler-DeWitt: H(phi) = 0 = the wavefunction of the Universe times the Hamiltonian (energy) of same = 0.

There's politics in everything I'm afraid. MWI was most likely an attempt by John Archibald Wheeler to show that Richard Feynman wasn't his only great charge, so he helped Hugh Everett III pursue his crazy idea. I'm sure MWI is mathematically tight, but Math isn't Physics.

My own view about Decoherence is yes it exists, but only up to a point. Literally, a point, a quanta, after which that event which disturbed the Universe may not, for all intents and purposes, have occurred at all from the point of view of everything beyond that.

Again from this Engineer's perspective and possibly wrong (which implies possibly right), Zero is the real deal but Infinity is just a concept. The wavefunction is continuous and is a nice approximation of reality, but reality gives only the illusion of continuity, and in fact we know we live in a discrete universe on the atomic and subatomic scales.

This is why I love Fourier Series and Analysis. On the smallest scales sine waves may become sawtooth waves, the excitations in the fields, the "particles."