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Electron at 0k

  1. Feb 22, 2008 #1
    What is the theory to explain how it still manages to survive.
  2. jcsd
  3. Feb 22, 2008 #2
    May I ask what is your definition of survival? Not turning into nothing?
  4. Feb 22, 2008 #3
    I know almost nothing about quantum physics but as far as I heard, there is always certian amount of minimum energy in system also called zero-point energy. You cannot have less than that amount of energy (Something to do with Planck scale). So Electron, nor any other particle can ever reach absolute 0k and therefore there is no problem with the electron survival.

    Last edited: Feb 22, 2008
  5. Feb 22, 2008 #4
    Do you perhaps mean that at 0K the atom's electrons should stop moving?
  6. Feb 22, 2008 #5


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    Not quite, due to the zero-point energy particles will move even at 0K.
    (Although this motion will be very small).
    Remember that there is no fundamental "equivalence" between motion and thermodynamic temperature, it is just that they happen to be related for e.g. a classical gas.
  7. Feb 22, 2008 #6
    Thanks for that correction.

  8. Feb 22, 2008 #7
    Even at 0k everything still moves.


    Because if it didn't we'd know it's position and momentum, which is a no-no.
  9. Feb 22, 2008 #8


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    It's not really a no-no, I thought that would come as a result of any attempted measurement on the particle, not simply knowing for sure that a particle is destined to be at place X with momentum = 0.
  10. Feb 22, 2008 #9
    If momentum were exactly zero, position would be infinitely wide. It literally could be found anywhere in the universe, and it woule be indistinguishable from any other electron, so you'd have no idea if that was "the one" you saw.
  11. Feb 22, 2008 #10
    A single electron in the middle of nowhere will just move in one direction forever. No reason to accelerate, ie no reason to vibrate. So it seems that temperature is undefined for a single electron with nothing nearby, or it's always 0K. Do the experts confirm?
  12. Feb 22, 2008 #11
    Electron survival

    As I recall, particles like electrons always survive unless there is a suitable reaction
    they can undergo that allows them to disappear. This limits their options. Getting rid of their energy is just one problem they have.

    Energy and momentum have to be conserved. Electrons have a rest mass, so even if they could stop moving they would have to get rid of the energy tied up in their rest mass before they could be allowed to leave. Momentum conservation normally means they have to hand over their momentum to another particle before they are allowed to go on holiday. There is also this thing called CPT symmetry, which lays down some rules about when they are allowed disappear.

    My understanding is that electrons tend to survive pretty well. They only seem to be allowed to get out of their responsibilities by meeting up with positrons or getting promoted to being a muon or something like that. This is very rare, they can't just pop out of existance when they are running low on energy.
  13. Feb 22, 2008 #12
    Does it depend on a genetic disposition? :smile:
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