Does Quantum Mechanics Suggest Photons Are Electrons and Positrons in a Cycle?

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Discussion Overview

The discussion revolves around the relationship between photons, electrons, and positrons in the context of quantum mechanics, particularly focusing on the processes of annihilation and creation. Participants explore theoretical implications and conditions under which these particles interact, including the role of energy and momentum conservation.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants propose that quantum mechanics might suggest a cyclical relationship between photons, electrons, and positrons.
  • Questions arise about whether an electron and positron can annihilate without the presence of a neutron, with some asserting that this is not necessary.
  • It is noted that while an electron and positron can annihilate to create a photon, this does not imply that all photons originate from such annihilation.
  • Concerns are raised regarding the probability of a photon spontaneously becoming an electron-positron pair, with some arguing that conservation laws prevent this from happening.
  • Participants discuss the conditions under which two colliding photons can create an electron-positron pair, and the requirement of sufficient energy for this process.
  • One participant mentions the path integral formulation of quantum mechanics, suggesting that a photon has a non-zero probability of existing as a virtual electron-positron pair.
  • There is a discussion about the role of a nucleus in facilitating pair production from a single photon, with emphasis on energy and momentum balance.
  • The influence of the electric field of a nucleus on the pair production process is questioned, with references to the nature of gamma rays involved.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the nature of photon interactions with electrons and positrons, particularly concerning annihilation and pair production. The discussion remains unresolved with no consensus on the implications of quantum mechanics in this context.

Contextual Notes

There are limitations regarding the assumptions made about energy and momentum conservation, as well as the specific conditions under which pair production occurs. Some mathematical details and definitions are not fully explored.

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Does QM tell us that photons are actually electrons and positrons goign through a cycle of annilation and creation?
 
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can an electron and positron annhilate each other without the presence of a neutron?
 
No, but an electron and a positron can annihilate to create a photon. this is not a statement about ALL photons.

Electron positron annihilation not have to happen in the presence of a neutron.
 
Is that to say there is a 0 probability of a photon going to a positron and electron?
 
A single photon cannot spontaneously become an electron and a positron, as it would be unable to simultaneously conserve energy and momentum. For the same reason, an electron and a positron cannot annihilate into a single photon.

However, two colliding photons (if they have sufficient energy) can form and electron and a positron; and, an electron and positron can annihilate to form two photons.
 
According to the path integral formulation of QM, a photon has a non-zero probability of spending time as a (virtual ?) e+/e- pair.
 
In addition to the 2 photon into electron-positron pair, it is possible for a single photon (of enough energy >1.22 Mev) to form a pair when in the presence of a nucleus to get the required energy and momentum balance. This reaction is quite common in nuclear reactors and in lead shielding.
 
Mathman, with the single photon near a nucleus, does the electric field of the nucleus play a part ? Presumably a 1.22 Mev photon is a gamma-ray type .
 
The electric field plays a role, since (I presume) the electromagnetic force is the only force involved. As far as the photon energy, yes it is a gamma ray. Gamma rays from nuclear reactors can be as high as 10 Mev (maybe even higher).

P.S. Error (by me) - threshold for pair production is 1.022 Mev, not 1.22.
 
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