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Einselection in Molecules

  1. Jan 27, 2016 #1
    In molecules, the system (say dna or ribosomes) environment are the cells.. id like to know how much is the momentum basis selected and how this can affect the molecules energies and to what extend and actual examples of that in this internal human body decoherence scenerio. Thank you.
     
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  3. Jan 27, 2016 #2

    bhobba

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    I would say not at all. Most interactions, and that certainly would be the interactions in a cell, are radial in nature (ie have rotational symmetry) and it is well known that singles out the position basis.

    Singling out the momentum basis is pretty much a contrived thing - not occurring naturally.

    Thanks
    Bill
     
  4. Jan 27, 2016 #3
    Could you give an example of inducing a molecular system to choose momentum basis? What would be the effect of it? Can it make the molecular have more kinetic energy?
     
  5. Jan 27, 2016 #4

    bhobba

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    I have zero idea how to do that.

    The only momentum outcomes I know of are contrived where you have a set-up designed to measure momentum.

    Thanks
    Bill
     
  6. Jan 28, 2016 #5
    Can you give example of a simple quantum system where the momentum is measured.. and does it mean the system has no position or localization? Or does momentum measurement also involve position?
     
  7. Jan 28, 2016 #6

    bhobba

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    Sure. Run an electron beam through a magnet an the circular path gives you the momentum. And no I cant really think of others - you will need to chat to an experimental type.

    Thanks
    Bill
     
  8. Jan 28, 2016 #7
    Does this this running electron beam through a magnet an the circular path giving the momentum also give the position? Or is there no localization?

    For molecules. Giving it more kinetic energy or even causing electron transitions is still related to position basis or momentum?
     
  9. Jan 28, 2016 #8
    added: but momentum is supposed to be the energy of the atom.. so I thought giving it more kinetic energy means it is momentum related...
     
  10. Jan 28, 2016 #9

    bhobba

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    Of course not - how does it tell the position of any electron in the beam.

    Thanks
    Bill
     
  11. Jan 28, 2016 #10

    bhobba

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    It isn't. That's really basic classical physics.

    Thanks
    Bill
     
  12. Jan 28, 2016 #11
    http://chemwiki.ucdavis.edu/Physica...nics/10:_Multi-electron_Atoms/Quantum_Numbers

    "The Orbital Angular Momentum Quantum Number (l'>l l )
    The orbital angular momentum quantum number l determines the shape of an orbital, and therefore the angular distribution. The number of angular nodes is equal to the value of the angular momentum quantum number l'>l"

    Mr. Hobba. The orbital angular momentum still use the position basis?? Then what is the momentum basis about?
     
  13. Jan 28, 2016 #12

    bhobba

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    Operators are basis independent, as are states.

    Sometimes the momentum basis is better for solving problems than the position basis - mostly the wave-function which is a state expanded in terms of the position basis is used, but sometimes its better to use the momentum basis - especially in Quantum Field Theory.

    Thanks
    Bill
     
  14. Jan 28, 2016 #13
    In QFT.. there is no position.. so no position basis is used.. but how come chairs and tables based on QFT (and momentum basis) has position and localizations?
     
  15. Jan 28, 2016 #14

    bhobba

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