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Hallo I'm trying to understand the concept of representation in the position space. I read that $|x\rangle$ are the eigenstates of the position operator, but I think this states should evolve in time since there aren't stationary states with a precise position?

What does $|x\rangle$ really mean?

Qmechanic
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SimoBartz
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1 Answers1

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The states $|x\rangle$ are eigenstates of the position operator, and they do not change with time.

That means that they are not solutions of the Schrödinger equation. This is fine: not every state in the Hilbert space* needs to evolve with time or obey the Schrödinger equation.

If you do take a position eigenstate as the initial state for a Schrödinger-equation evolution, then the state will obviously evolve, since it is not in an eigenstate of the hamiltonian. For a free particle, it will immediately spread over all of space; for the details, see The Dirac-delta function as an initial state for the quantum free particle.


*That's a minor cheat - the position eigenstates are not actually in the Hilbert space. That doesn't affect the conclusions, though.

Emilio Pisanty
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