Electron Self-Energy: QED Calculation & Verification

In summary, the conversation is about calculating the three infinities in QED, specifically the vacuum polarisation, vertex corrections, and electron self-energy. The speaker has been following a description in a book but is unable to find the result for the electron self-energy. They are asking for help and clarification on this concept. The electron self-energy is explained as occurring in classical electrodynamics and can be calculated in QED. It involves the Green's function G(x,y) and is solved with renormalization. The relationship between G(x,y) and the potential is also mentioned.
  • #1
blackie1008
5
0
Hi,

I have been calculating the 3 infinities in QED as part of my project (vacuum polarisation, vertex corrections and electron self energy). Mostly I have been following the description in Mandl and Shaw for determining the first two (chapter 10, sections starting on p211). However it does not explicitly calculate, or state (as far as I can see) the result for the electron self-energy. I was wondering if there was anywhere that I could be pointed too so that I can check my result? I have been trawling the web, but to no avail...

Help would be much appreciated thanks!
 
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  • #2
Just wondering, what exactly is Electron Self Energy?
 
  • #3
Drakkith said:
Just wondering, what exactly is Electron Self Energy?

The electron self-energy occurs in classical electrodynamics where if you calculate the potential of an electron at the point of the electron, you get infinity.

In classical electrodynamics this is ignored, but can be calculated in QED.

In QED the Green's function G(x,y) which represents propagation from spacetime point x to y (or the interaction of the field at x with the field at y) blows up when taken at the same point G(x,x). Note that such self-interactions are not taken into account in classical statistical mechanics.

G(x,x) is solved with renormalization.

The relationship between G(x,y) and the potential is:

V(r1,r2)=(2π)Integral d3k ei(ki(x-y)i)G00(k0=0,ki)
 

1. What is electron self-energy in quantum electrodynamics (QED)?

Electron self-energy is a concept in quantum electrodynamics that describes the interactions between an electron and its own electromagnetic field. In other words, it is the energy a lone electron has due to its own presence.

2. How is electron self-energy calculated in QED?

In QED, electron self-energy is calculated using perturbation theory, specifically the Feynman diagram approach. This involves summing up an infinite series of Feynman diagrams to account for all possible interactions between the electron and its own field.

3. Why is it important to calculate and verify electron self-energy in QED?

The calculation and verification of electron self-energy in QED is important for understanding and accurately predicting the behavior of electrons in quantum systems. It also helps to improve the precision and accuracy of experimental results in areas such as high-energy physics and quantum computing.

4. How is electron self-energy verified experimentally in QED?

Electron self-energy can be indirectly verified through experiments such as measuring the Lamb shift, which is the energy difference between two energy levels in a hydrogen atom. This shift is caused by the self-energy of the electron in the atom.

5. Are there any challenges or limitations in calculating and verifying electron self-energy in QED?

One of the main challenges in calculating and verifying electron self-energy in QED is the need to account for an infinite number of Feynman diagrams, which can be computationally intensive. Additionally, there may be limitations in our current understanding and models of QED, which can affect the accuracy of calculations and verifications.

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