How does an electron interact in QFT?

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    Electron Qft
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Discussion Overview

The discussion revolves around how electrons interact within the framework of Quantum Field Theory (QFT), particularly focusing on the nature of their interactions when they are not localized. Participants explore concepts related to electron repulsion and the role of the electromagnetic field in these interactions.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions how electrons interact if they are not localized, suggesting that understanding this is crucial for grasping quantum theory.
  • Another participant describes electrons as excitations of the electron field that interact locally, drawing an analogy to water wavelets.
  • It is noted that the interaction term of the electron field current with the photon field is analogous to classical interactions, where charged particles do not need to be in the same position to interact.
  • Participants discuss the idea that electrons create disturbances in the electromagnetic field around themselves, which facilitates their interactions.
  • A reference is made to previous discussions on how the force between charged particles arises in QFT, indicating ongoing exploration of this topic.

Areas of Agreement / Disagreement

Participants express various viewpoints on the nature of electron interactions in QFT, with no clear consensus reached on the specifics of how these interactions occur when electrons are not localized.

Contextual Notes

Some statements rely on classical analogies, and there is an acknowledgment of the complexity involved in understanding quantum interactions. The discussion includes references to previous threads that may provide additional context.

Philipsmett
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How does the electrons interact in QFT? if they are not localized? For example, when one electron repels another or does an atom repel another atom? How do electrons find each other for interaction?
 
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They are excitations of the electron field which interacts locally. Like water wavelets, but quantum and hence more complicated...
 
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I would just add that the interaction term of the electron field current ##\bar e \gamma^\mu e## is with the photon field. This is also true classically. Even classically charged particles do not interact by being in the same position, they interact through their interaction with the classical electromagnetic field.
 
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Orodruin said:
I would just add that the interaction term of the electron field current ##\bar e \gamma^\mu e## is with the photon field. This is also true classically. Even classically charged particles do not interact by being in the same position, they interact through their interaction with the classical electromagnetic field.
How do two electrons interact if they are not localized?
 
Philipsmett said:
How do two electrons interact if they are not localized?
Classically, electrons are localised, but they do not need to be in the same position to interact with each other. The reason for this is that they interact via their interactions with the electromagnetic field. Compare with the force between two magnets which is there even if they are not in the same place. You need to understand this in order to have any cance of understanding the quantum theory.
 
Orodruin said:
Classically, electrons are localised, but they do not need to be in the same position to interact with each other. The reason for this is that they interact via their interactions with the electromagnetic field. Compare with the force between two magnets which is there even if they are not in the same place. You need to understand this in order to have any cance of understanding the quantum theory.
That is, electron create around themselves disturbances in the electromagnetic field?
 
Philipsmett said:
That is, electron create around themselves disturbances in the electromagnetic field?

Loosely you could express it that way.

The following may help:
http://www.physics.usu.edu/torre/3700_Spring_2015/What_is_a_photon.pdf

As explained above the coupling mentioned previously is responsible for real effects such as spontaneous emission that can not be explained any other way.

How the force between charged particles arises in QFT has been discussed in other threads:
https://www.physicsforums.com/threads/electron-repulsion-in-qft.964567/#post-6121372

Thanks
Bill
 

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