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How do wavefunctions deal with energy (of the photon)? 
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#1
Jan3013, 10:41 AM

P: 915

1. Are wavefunctions, in some situations, also assumed to carry energy with them?
2. Can wavefunctions be used to show/validate the law of conversation of momentum/energy? 3. In a single particle double slit/path experiments, if one path is blocked what happens to the wavefunction ? and the energy? 4. Per the debroglie bohm (DBB) interpretation: In de Broglie–Bohm theory, the wavefunction travels through both slits, but each particle has a welldefined trajectory and passes through exactly one of the slits. If the wavefunction (per DBB is hypothesized) is to be travelling through both the slits, how is (the energy of) the photon supposed to be travelling? In single particle interference (for example single particle double slit, or single particle through a MachZehnder) the particle interferes with "itself". The path of the photon is different (when there is interference) than the path when there is no interference. Thus energy must be involved (at least per classical mechanics) during interference. ....to change the path of a photon 


#2
Jan3013, 12:12 PM

P: 877

I think you should clearly distinguish between *forces*, which are what deflects particles' trajectories in classical mechanics, and *energy*, which is just a property of a particle's motion. The status of forces in quantum mechanics is actually quite interesting. Namely, force isn't a concept that really enters into quantum mechanics at all. Instead we deal with potential energy (force is the gradient of potential energy). 


#3
Jan3113, 01:27 AM

P: 915

So, in the above case: Is the energy of the photon prior to encountering the slit different than later? ...because part of the energy has been absorbed (or reflected) by the obstacle...(?) 


#4
Jan3113, 05:11 PM

P: 877

How do wavefunctions deal with energy (of the photon)?
1) the photon has passed through the open slit, maintaining the same energy it had before, or 2) the photon has been absorbed by the obstacle and destroyed, or 3) the photon has been reflected by the obstacle and has the same energy it had before. 


#5
Feb113, 03:13 AM

P: 915

thanks The Duck
Re:The part of the wavefunction that is absorbed (by the obstacle); what happens to the energy carried/associated with it? ....say, per the wavefunction treatment 


#6
Feb113, 09:46 PM

P: 877

It sounds like you are under the impression that the energy is spread out throughout the wave function in some fashion, so that we could say something like, "our photon has a total energy of 6 eV, 4 eV of which is carried by this part of the wave function and 2 eV of which is carried by this other part of the wave function." This is not the case.
When part of the wave function hits a barrier and is absorbed, and the other part doesn't, the interpretation is "with some probability the photon has been absorbed by the barrier and deposited all 6 eV of its energy, and with some probability the photon has missed the barrier, carrying all 6 eV of its energy with it and depositing none in the barrier." As a somewhat glib and inaccurate summary: the wave function is made of probability, not energy. 


#7
Feb113, 09:57 PM

P: 915




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