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What is a particle in quantum mechanics?

  1. Nov 9, 2014 #1
    I would imagine that there are different viewpoints of what a particle is in quantum mechanics. Is it possible to get a summary of what they are?
  2. jcsd
  3. Nov 9, 2014 #2


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    Something that is detected by a particle detector, i.e. something that shows up as a dot on a screen, or some such.
  4. Nov 9, 2014 #3
    A discrete excitation of a quantum field which is characterized by the eigenvalues of some set of conserved operators (e.g. charge, mass, and spin). They are often, but not necessarily, well-localized in space.
  5. Nov 10, 2014 #4


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    The definition in post#3 reminds me of the famous one by E.P. Wigner which can be recast as: A particle is a quantum state in the (rigged) Hilbert space which carries an irreducible representation of the universal covering group of the restricted Poincare group.
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