Screening in QED: Electron, Positron, and Gauss's Law

In summary, the conversation discusses the concept of screening in QED and vacuum polarization. The use of an electron surrounded by rings of positrons and electrons helps to explain this concept. The Gauss's law applies both inside and outside the rings, resulting in the same electric field for particles inside and outside the rings. However, the charge outside the rings appears to be smaller than inside. The speaker is unsure of the reason for this and the other person explains that the images used are heuristic and do not accurately represent the situation. The question remains of how to think about this concept without relying on the images.
  • #1
Silviu
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Hello! I read today about the screening in QED and vacuum polarization. And the image they used to explain it was an electron surrounded by a ring of positrons and then by a ring of electron, which makes sense. Now, the Gauss's law outside and inside the 2 rings will give the same result, as the charge inside a sphere centered on the electron will enclose just the charge of the electron as the positron and electron rings will cancel each other, when the sphere is outside them. So for a particle outside or inside the 2 rings, the electric field (times the distance to the electron squared) it feels is the same. So I am not sure I understand why the charge outside the 2 rings seems to be smaller than inside them. Thank you!
 
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  • #2
Such images are purely heuristic and does not carry any actual information or are representative of what is going on.
 
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  • #3
Orodruin said:
Such images are purely heuristic and does not carry any actual information or are representative of what is going on.
So how should I think about it?
 

Related to Screening in QED: Electron, Positron, and Gauss's Law

1. What is screening in QED?

Screening in QED (Quantum Electrodynamics) is a phenomenon where the electric field of a charged particle is reduced or cancelled out by the presence of other charged particles in its vicinity. This is due to the exchange of virtual photons between the particles, resulting in a shielding effect.

2. How does screening affect electrons and positrons?

In QED, the presence of an electron and a positron creates a screened potential that is weaker than the potential created by just a single electron or positron. This is because the virtual photons exchanged between the particles can cancel out some of the electric field.

3. What is Gauss's Law and how does it relate to screening in QED?

Gauss's Law is a fundamental law in electromagnetism that relates the electric flux through a closed surface to the charge enclosed by that surface. In QED, Gauss's Law is used to explain the electric field screening effect between charged particles.

4. Can screening in QED be observed in experiments?

Yes, screening in QED has been observed in various experiments, including the Lamb shift and the anomalous magnetic moment of the electron. These experiments provide evidence for the existence of virtual particles and their role in screening effects.

5. How does screening in QED affect the behavior of particles in high-energy accelerators?

In high-energy accelerators, particles are accelerated to very high speeds and energies. In this extreme environment, screening effects become more significant as there are more virtual particles being exchanged between the accelerated particles. This can affect the trajectory and behavior of the particles, making it important to consider screening effects in these experiments.

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