Re:What’s Going on During Wave Function ‘Collapse’
by lisper on Friday July 05, 2019 @04:44PM
(#20365740)
> once you split off branches that have factors living in different eigenspaces
And how exactly does that happen?
The answer is: it doesn't. The orthogonality of different branches is an approximation. It's a very good approximation because decoherence is a phenomenally efficient process, but it's an approximation nonetheless. The universal wave function always resides in the same Hilbert space because, as you yourself pointed out, Schrödinger time evolution is linear and unitary.
And how exactly does that happen?
The answer is: it doesn't. The orthogonality of different branches is an approximation. It's a very good approximation because decoherence is a phenomenally efficient process, but it's an approximation nonetheless. The universal wave function always resides in the same Hilbert space because, as you yourself pointed out, Schrödinger time evolution is linear and unitary.