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Is free electron's motion quantized?

  1. Nov 27, 2006 #1
    is free electron's motion quantized?

    For example if i knock off electron from an atom and than trap it inside some space where i can manipulate magnetic fields, can i slow and speed up the electron continuously, or will the electron speed be quantized?

    please, explain why is it quantized?
  2. jcsd
  3. Nov 27, 2006 #2
    Any quantization arises from the boundary conditions of the wave function. Of course, in the case of the magnetic field (in a semi-classical picture), you'll find some sort of quantization of the rotation around the magnetic fields because the particles rotate around them and the angular momentum is quantized.

    Quantization is a consequence of various kinds of boundary conditions, usually.
  4. Nov 27, 2006 #3
    That makes sense, thank u
  5. Nov 27, 2006 #4
    I would like to extend the question.

    Can electron moving in quantized circular obit 'slow down' or decrees in energy level other way than by emitting a photon?

    For example is there i way to slow down an electron by the magnetic fields 'continuously' until it will make 'jump' to lower orbit without emitting a photon?

    in general: is the only way to change orbitals to emit photons? or is there another way without emitting the photon?
  6. Nov 27, 2006 #5
    The most accurate forum for the discussion of interaction of particles and fields is QED, however QED is very ambigous when it comes to bound state problems. You can adiabatically change the strength of a magnetic field within a first quantised theory and the energy eigenvalues will change continuosly. If it done adiabatically as zero temperature then the particle will remain in the ground state, its energy changing continuously. There is a thery by Gell-mann and Lowe with regard to this.

    In QED, External field need not be quantised and as such I would say that yes, this would be possible. The particle will remain in the ground state without the emission of a photon if the potential is altered adiabatically (very slowly such that the system reamins in equilibrium).
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