- #1
fluidistic
Gold Member
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Imagine a system of 1 particle in a superposition of eigenstates of some operator(s). If one were to make a measurement of a property of that particle, how is the operator (or observable) "picked" so that the wavefunction collapses into an eigenstate of said operator? In other words, how do one make the wavefunction collapse into say an energy eigenstate as opposed to a position eigenstate? I already know that it's by "measuring the energy of the particle", this is not what I am asking. I am asking what makes the measurement measuring the energy instead of other properties, in that case.
Another concrete example would be a Bloch electron in a solid. Atoms in the lattice are constantly measuring its energy, I think, and never its momentum nor position. I'd like to derive this fact from first principle. And then move on to Cooper pairs, etc. (where I am not sure, but I think the lattice still constantly measure the energies of Cooper pairs, but I'd like to derive it from first principles).
Another concrete example would be a Bloch electron in a solid. Atoms in the lattice are constantly measuring its energy, I think, and never its momentum nor position. I'd like to derive this fact from first principle. And then move on to Cooper pairs, etc. (where I am not sure, but I think the lattice still constantly measure the energies of Cooper pairs, but I'd like to derive it from first principles).