To me, the beginning of the approaching of an electron-positron pair and an electron-proton pair look somehow the same. There is a spatial attraction and in the process there is an energy emission in the form of a series of photons.

Where are the differences, except of course for the different end of the two processes?


1 Answer 1


Electrons and positrons are quantum mechanical entities. At large distances approaching each other the formulae for possible radiation are the same, because the charge set up is the same. The approach of an electron on a proton was one of the reasons quantum mechanics had to be invented. Instead of the electron radiating continually and falling on the proton, quantized spectra were found and the hydrogen atom was created.

The same is true for an electron approaching the positron, the bound states of positronium are found, with its energy level spectrum.

The probabilistic wave functions for both hydrogen and positronium have a probability for the two particles to overlap. In the case of hydrogen quantum numbers conservation does not allow capture or annihilation of the electron, For positronium it allows for the annihilation of both electron and positron into photons.

P.S. there is a recent experiment on the energy levels of positronium that might be of interest .

  • $\begingroup$ what do you mean by "when" ? In mainstream physics the Feynman diagram of annihilation can answer the "when". $\endgroup$
    – anna v
    Apr 1, 2022 at 6:44
  • $\begingroup$ I will pose a new question about at what point of approach the charges of the two antiparticles disappear. And how this is relevant to the electron-proton interaction. Or Anna can you please answer this in your reply. $\endgroup$ Apr 1, 2022 at 14:16
  • $\begingroup$ physics.stackexchange.com/questions/701762/… $\endgroup$ Apr 2, 2022 at 4:38

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