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UP regarding value of a field and its rate of change

  1. Oct 19, 2013 #1

    Suwailem

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    I am just a hobbyist and try to learn for myself.

    I understand that the value of a field and its rate of change play the same role of position and momentum of a particle with respect to Uncertainty Principle, i.e. both pairs are conjugate variables. My question is: does the rate of change of a field extends to the negative domain, so that it could take negative values, or is it always non-negative?
     
  2. jcsd
  3. Oct 19, 2013 #2
    Derivative of a field can be negative and it often is negative. If it were always positive (or zero), the field value would be always and forever growing (or not changing).
     
  4. Oct 19, 2013 #3

    Suwailem

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    Thank you mvp_plate.
     
  5. Oct 19, 2013 #4

    Suwailem

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    If the momentum is always positive (or non-negative), then the analogy of momentum with rate of change will not be one to one?
     
  6. Oct 19, 2013 #5

    Nugatory

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    Momentum is not always non-negative. Consider two bodies of equal mass moving in opposite directions: their momenta will be of equal magnitude but opposite sign, so the total momentum of the system is zero.
     
  7. Oct 19, 2013 #6

    Suwailem

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    Thank you Nugatory.
     
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