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Superfluous Superposition

  1. Aug 7, 2003 #1
    right, um, deconstructive inteference; where does the energy go? [?]
  2. jcsd
  3. Aug 7, 2003 #2
    It is my understanding that any wave entity oscillates between positive and negative. At a point of complete deconstructive interference, (+x)+(-x)=0, x being half the peak to peak energy difference. Statistically, there was no net energy in either wave in the first place.
  4. Aug 7, 2003 #3
    Yer but it's like the whole notion of "negative" energy, I find it kinda confuddling
  5. Aug 7, 2003 #4


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    Perhaps it is a problem of trying to deal with the wave as an isolated identity. In a wave train, if two waves interfere destructively, then somewhere else along the way two other waves interfere constructively, do they not? As for negative energy, it is less confusing when viewed in context. According to the principle of quantum inequality, any amount of negative energy can only exist withtin or as a part of a system that contains a greater amount of positive energy. So the net energy is always positive.
  6. Aug 7, 2003 #5
    In reference to there being a constructive inteference as well accounting for the lost energy, I suppose it would come down to an issue of time; so if you experimentally arranged it so that the waves inteferred deconstructively first, what has happened to the energy at that point in time, before the constructive superposition occurs? And in terms of negative energy, I thought a system could only be said to have negative energy when it's doing work.
  7. Aug 8, 2003 #6


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    In most wave iteractions the energy is transfered between two different modes. While one mode experiances a minimun the other is at a maximum. The modes of an Electromagnetic field are the electric field and the magnetic field. So while you are obseving a phenomena miniumn related to the electric field at the same time and same point in space the magnetic field is experianceing a maximum. So destructive interferance for one will be constructive for the other.
  8. Aug 8, 2003 #7
    Wot about when it isn't transferred between different modes?
  9. Aug 8, 2003 #8


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    Long ago, like in the 60's, I read about an experiment where a beam of neutrons from a reactor was made to interfere destructively with itself. And according to the article the neutrons did cease to exist. And I too wondered, what happened to their mass energy?
  10. Aug 8, 2003 #9
    Energy is so nebulous a concept that it never bugged me when deconstructive interference occured. But that neutrons do sometimes cease to exist when acting like waves, I find that baffling.
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