How does an electron interact in QFT?

In summary, the interaction between two electrons in QFT is mediated by their interactions with the electromagnetic field, rather than being dependent on their physical proximity. This is similar to the way two magnets can interact even when not in the same position. This concept is important in understanding the quantum theory and has been discussed in various sources.
  • #1
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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  • #3
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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  • #4
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?
 
  • #5
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.
 
  • #6
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?
 
  • #7
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
 

1. What is QFT?

QFT stands for Quantum Field Theory. It is a theoretical framework that combines quantum mechanics and special relativity to describe the interactions between particles at the subatomic level.

2. How does an electron interact in QFT?

In QFT, electrons are described as excitations of the electron field. These excitations interact with other fields, such as the electromagnetic field, through the exchange of virtual particles. This interaction is described by mathematical equations known as Feynman diagrams.

3. What is the role of symmetry in electron interactions in QFT?

Symmetry plays a crucial role in QFT, as it allows us to predict the behavior of particles and their interactions. The symmetries of a system are described by mathematical equations known as gauge symmetries, which are essential in the development of QFT models.

4. How is the concept of spin incorporated in QFT?

In QFT, spin is described as an intrinsic property of particles. It is incorporated into the mathematical framework through the use of spinors, which are mathematical objects that represent the spin of a particle. The spin of a particle affects its interactions with other particles and fields.

5. What are the limitations of QFT in describing electron interactions?

While QFT has been incredibly successful in describing the interactions of particles at the subatomic level, it has some limitations. For example, it does not take into account the effects of gravity, and it cannot fully explain the behavior of particles at extremely high energies. These limitations have led to the development of more advanced theories, such as string theory and loop quantum gravity.

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