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I do not want answers telling me that wave-function collapse is not real and decoherence is the answer (I know the situation with that). I am asking a question purely on the basis if wave-function collapse is the correct method. My question is: in normal quantum mechanics superposition of the state (position, momentum) exists until the wave-function collapses (how or why it collapses is not important in this question), now in quantum field theory we can also have superposition as in the superposition of Fock space states with different particle number. Can the superposition also collapse here under collapse interpretations of quantum mechanics/quantum field theory?

Laymans answers would be mainly appreciated...

Hunter
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lee hudson
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1 Answers1

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Quantum field theory does not have a special place within quantum mechanics as regards the Measurement Problem, or any of its proposed solutions. QFT is simply quantum mechanics when applied to a specific system, whose dynamical variables are the infinite degrees of freedom of a field. Just as in standard quantum mechanics, states are vectors in a Hilbert space (which can therefore be added together to give superposition states), and observables are operators on it. The collapse of a wavefunction - or its decoherence, or splitting off into different branches as it gets entangled with a measurement apparatus - looks exactly the same.

Emilio Pisanty
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