Understanding Electrons: The Difference Between QFT and QED

In summary: Yes, it's the excitation of electron field. Excitations of electromagnetic fields are photons. Maybe what he meant is that electrons are not exscitations of electromagnetic field.
  • #1
Philipsmett
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What different between QFT and QED? In QFT electron is field quanta, what is electron in QED?
 
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  • #2
QED is a type of quantum field theory. QFT is just a way of modeling quantum phenomenon and doesn't necessarily refer to a specific model. I believe there are several gauge theories that are also quantum field theories, but I could be mistaken.
 
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  • #3
Yes, QED (for electromagnetic interactions) is an example of a QFT. Other examples of QFTs are quantum chromodynamics (QCD) for the strong interaction, and electroweak theory, sometimes called quantum flavordynamics (QFD) for the unified electromagnetic and weak interactions.
 
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  • #4
Drakkith said:
QED is a type of quantum field theory. QFT is just a way of modeling quantum phenomenon and doesn't necessarily refer to a specific model. I believe there are several gauge theories that are also quantum field theories, but I could be mistaken.
What is electron in QED? Is it field quanta?
 
  • #5
Philipsmett said:
What is electron in QED? Is it field quanta?

QED is a QFT, so an electron in QED is whatever it is in QFT. And you already said what it is in QFT in your first post.
 
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  • #6
PeterDonis said:
QED is a QFT, so an electron in QED is whatever it is in QFT. And you already said what it is in QFT in your first post.
Why did Feynman say that the electron is a particle and not a field quanta?
 
  • #7
Philipsmett said:
Why did Feynman say that the electron is a particle and not a field quanta?

A particle is a field quantum.
 
  • #8
PeterDonis said:
A particle is a field quantum.
that is, the electron in QED is the excitation in the field?
 
  • #9
Yes, it's the excitation of electron field. Excitations of electromagnetic fields are photons. Maybe what he meant is that electrons are not exscitations of electromagnetic field.
 
  • #10
Philipsmett said:
the electron in QED is the excitation in the field?

It's an excitation of the electron field. As @weirdoguy said. QED contains two fields, the electron field and the electromagnetic field. Photons are excitations of the electromagnetic field.
 
  • #11
FYI, Feynman came over to the field viewpoint later in life - see reference in Julian Schwinger's Climbing the Mountain.
 

1. What is an electron in QED?

An electron in QED (Quantum Electrodynamics) is a fundamental subatomic particle that carries a negative charge and is a building block of matter. It is also considered to be a point-like particle, meaning it has no internal structure.

2. What is the role of electrons in QED?

Electrons play a crucial role in QED as they are one of the two types of elementary particles that interact through the electromagnetic force. They interact with other particles by exchanging virtual photons, which is the basis of quantum electrodynamics.

3. How does QED describe the behavior of electrons?

QED describes the behavior of electrons using the principles of quantum mechanics and special relativity. It explains how electrons can exist in multiple states simultaneously and how they interact with other particles through the exchange of virtual photons.

4. What are the properties of an electron in QED?

Electrons in QED have several properties including mass, charge, spin, and magnetic moment. They also have an anti-particle counterpart, the positron, which has the same properties but with a positive charge.

5. How does QED explain the behavior of electrons in different environments?

QED can explain the behavior of electrons in different environments by taking into account the effects of the surrounding particles and fields. It can also predict how the electrons will behave in different energy levels and under different forces, such as in an electric or magnetic field.

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