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The photoelectric effect and Compton scattering can both be explained with a semi-classical theory in which there are no photons. Can try and dig up papers if

The photoelectric effect and Compton scattering can both be explained with a semi-classical theory in which there are no photons. Can try and dig up papers if you are interested. Not familiar with squeezed states. The only quantisation needed in the Casimir effect is boundary-induced quantisation, that EM waves should have, right? EDIT: for example: https://thiscondensedlife.wordpress.com/2019/08/25/ https://thiscondensedlife.wordpress.com/2019/08/25/

jpmattia 3y ago
Yes, let's see references, especially for the multiphoton processes in Compton. > The only quantisation needed in the Casimir effect is boundary-induced quantisation, that EM waves should have, right? No. You need to explain why there is attraction in the absence of EM waves. fyi the various noise measurements from squeezed states might hold interest for you.
- Ono-Sendai 3y ago
  You can have vacuum fluctuations without photons. EDIT: will try and find Compton paper later, going for walk now.
  - defrost 3y ago
    Looking forward to your return, I'll be making popcorn :-) Nice to see a stand taken on uncommon ground.
  - jpmattia 3y ago
    > You can have vacuum fluctuations without photons. Casimir is not about fluctuations. There is an attraction between metal plates in the absence of electromagnetic radiation. And as I think it through, an even simpler example is the laser. Bose-Einstein statistics require that you have indistinguishable particles to multiply occupy a state. Without the indistinguishability, you don't end up with the right statistics. Without the right statistics, you don't end up with the right Einstein rate equations, and you'll be missing the stimulated emission term. Without that term, you will be missing the lasing action, as well as secondary effects such as noise statistics.
- Ono-Sendai 3y ago
  Oh apparently it was Schrodinger himself that wrote about a semiclassical Compton scattering approach: http://www.regels.org/Compton-effect.htm http://www.regels.org/Compton-effect.htm
  - jpmattia 3y ago
    So Strnad is an interesting paper (I put the full cite as [1].) My take after skimming [1] plus references therein, plus those that cited [1]: There is a cottage industry of papers trying to replay the early work on QED. Each paper takes one effect as it was known around 1930 or so, and then explains it using something other than QED. I find the papers interesting in an academic sense. However, as guidance for how the world works, they build a box around the things they are trying to explain, but ignore the more difficult aspects of experimental data found after the 1930s. For the case of Compton, there are higher order scattering processes which lead to nonlinear Compton scattering, which happened in the 1960s. To make a specific answer to your comment: My quick read is that Schrodinger's explanation fails at higher intensities, since the semiclassical treatment of E&M will increase only the amplitude of the radiation field, whereas nonlinear Compton scattering will need something in the way of additional terms or mechanisms to explain the experimental results. More generally, that set of papers seemed to address only the singleton mechanisms but ignored the more general problem of noise and statistics. For example: Increasing the field amplitude in various experiments will reveal the shot-noise profile of photons, but I saw nobody try to approach that problem in my brief survey. In any case, thanks for the reference. It lead to some interesting reading. [1] Strnad, J. (1986). The Compton effect-Schrodinger’s treatment. European Journal of Physics, 7(4), 217–221. doi:10.1088/0143-0807/7/4/001
    - Ono-Sendai 3y ago
      Glad you like it. I haven't gone through any of the maths in detail. I do however have a semi-classical electrodynamics computer simulation that I occasionally work on, so why do the maths when you can just run a simulation :) When I get back to it maybe I will try and simulate Compton scattering or the photoelectric effect.

jpmattia 3y ago

Yes, let's see references, especially for the multiphoton processes in Compton. > The only quantisation needed in the Casimir effect is boundary-induced quantisation, that EM waves should have, right? No. You need to explain why there is attraction in the absence of EM waves. fyi the various noise measurements from squeezed states might hold interest for you.

Ono-Sendai 3y ago
You can have vacuum fluctuations without photons. EDIT: will try and find Compton paper later, going for walk now.
- defrost 3y ago
  Looking forward to your return, I'll be making popcorn :-) Nice to see a stand taken on uncommon ground.
- jpmattia 3y ago
  > You can have vacuum fluctuations without photons. Casimir is not about fluctuations. There is an attraction between metal plates in the absence of electromagnetic radiation. And as I think it through, an even simpler example is the laser. Bose-Einstein statistics require that you have indistinguishable particles to multiply occupy a state. Without the indistinguishability, you don't end up with the right statistics. Without the right statistics, you don't end up with the right Einstein rate equations, and you'll be missing the stimulated emission term. Without that term, you will be missing the lasing action, as well as secondary effects such as noise statistics.
Ono-Sendai 3y ago
Oh apparently it was Schrodinger himself that wrote about a semiclassical Compton scattering approach: http://www.regels.org/Compton-effect.htm http://www.regels.org/Compton-effect.htm
- jpmattia 3y ago
  So Strnad is an interesting paper (I put the full cite as [1].) My take after skimming [1] plus references therein, plus those that cited [1]: There is a cottage industry of papers trying to replay the early work on QED. Each paper takes one effect as it was known around 1930 or so, and then explains it using something other than QED. I find the papers interesting in an academic sense. However, as guidance for how the world works, they build a box around the things they are trying to explain, but ignore the more difficult aspects of experimental data found after the 1930s. For the case of Compton, there are higher order scattering processes which lead to nonlinear Compton scattering, which happened in the 1960s. To make a specific answer to your comment: My quick read is that Schrodinger's explanation fails at higher intensities, since the semiclassical treatment of E&M will increase only the amplitude of the radiation field, whereas nonlinear Compton scattering will need something in the way of additional terms or mechanisms to explain the experimental results. More generally, that set of papers seemed to address only the singleton mechanisms but ignored the more general problem of noise and statistics. For example: Increasing the field amplitude in various experiments will reveal the shot-noise profile of photons, but I saw nobody try to approach that problem in my brief survey. In any case, thanks for the reference. It lead to some interesting reading. [1] Strnad, J. (1986). The Compton effect-Schrodinger’s treatment. European Journal of Physics, 7(4), 217–221. doi:10.1088/0143-0807/7/4/001
  - Ono-Sendai 3y ago
    Glad you like it. I haven't gone through any of the maths in detail. I do however have a semi-classical electrodynamics computer simulation that I occasionally work on, so why do the maths when you can just run a simulation :) When I get back to it maybe I will try and simulate Compton scattering or the photoelectric effect.