Fundamental Process of an electron absorbing a photon

[actionintegral]

Got it - thanks!

 

[Abu Abdallah]

it's conservation laws that prohibit a free particle from absorbing or emitting a photon while remaining a free particle.

Reilly,
your reply was very informative. Conservation laws provide good reasons for us to understand why an interaction can happen or not, but for the particle itself I think there should be a more fundamental reason. The particle doesn't know that charge, for example , has to be conserved, but any possible interaction that the particle can go through should conserve charge. Take another example: a ball at rest on the ground doesn't go upwards by itself against gravity. We can say that's because the energy will not be conserved in this case, but the real reason that the charge understands is that there is no thing (force) that pushes it upwards, so why take the trouble? I know that this may seem useless for some people, but this is the level of understanding I aim to.

The plain fact is the the assumption of emission and absorbtion of photons is not really that much different than Maxwell's conclusion that acceleration of charged particles causes radiation -- we get the "how", but the why is not really explained classically or quantumly (sorry 'bout that).

I hope you elaborate on that. How can the process of producing photons classically- acceleration of charges- be similar to photon production in quantum mechanics- transition between different states.? I hope I can find a treatment that unifies both processes, since I think they should be two faces of the same process, the final products of them are the same: photons !


Abu AbdAllah

 

[actionintegral]

Revisiting

To me this was a good question because it made me think a lot.

The creation of a photon requires the "infrastructure" of an harmonic oscillator. I say this because I look at the shrodinger equation and it contains a macroscopic harmonic oscillator potential.

Therefore, it seems to me, that to absorb a photon, one must already have an harmonic oscillator in place. Whether the photon is absorbed by an electron or something else is secondary. The photon is absorbed by an harmonic oscillator.