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Single electron wave packet in Fock space?

  1. Jun 22, 2015 #1
    How might we construct a state most closely corresponding to the idea of a single electron wave packet as some superposition of Fock states?
  2. jcsd
  3. Jun 23, 2015 #2


    Staff: Mentor

    I don't think that's compatible with the QFT formalism of a superposition of 0 particle, 1 particle, 2 particle states etc - but someone who knows more than I do may have an answer - I certainly don't. A wave-packet is of a single particle.

  4. Jun 23, 2015 #3

    A. Neumaier

    User Avatar
    Science Advisor

    It is a pure Fock state in its 1-particle sector. A general Fock state has the form $$\psi=\psi_0+\psi_1+\psi_2+\ldots$$ of a superposition of N-particle states \psi_N. In a momentum representation the latter are of the form $$\psi_N=\int dp_1...dp_N \psi_N(p_1,\ldots,p_N)|p_1,\ldots,p_n\rangle$$. Now put all \psi_N to zero except for N=1, and you can translate your wave packet exactly into a state in Fock space.
    Last edited: Jun 23, 2015
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