Do virtual particles interact?

In summary, the conversation discusses virtual particles and their interactions with ordinary particles. The concept of virtual particles being constantly created and destroyed in a vacuum is mentioned, and the question of whether these particles can collide with each other is raised. The response explains how vacuum loop diagrams can illustrate these interactions and also mentions how virtual particles interact with normal particles. The conversation also touches on the topic of vacuum polarization and its effects on atomic energy levels. The conversation ends with a request for resources to further understand these concepts.
  • #1
Lino
309
4
(First off, I'm not sure that I'm asking this question in the right area, but there does seem to be other questions associated with the topic, so hopefully I'm ok, but if I'm wrong, apologies.)

I understand that virtual particles are... virtual, a mathematical construct that is used to describe certain scenarios, but does the math allow virtual particles to interact with each other / ordinary particles? For example, within a vacuum, virtual particle / anti-particle pairs are constantly being "created"and "destroyed", so does the math allow for "collision" (changing the virtual / mathematical trajectory) between the virtual particle of pair A and the virtual particle of pair Bs, and does the math allow the virtual anti-particle from pair A to "destroy" the virtual particle from pair B?

Thanks for your help,

Noel.
 
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  • #2
Lino said:
I understand that virtual particles are... virtual, a mathetical construct that is used to describe certain scenarios, but does the math allow virtual particles to interact with each other / ordinary particles? For example, within a vacumn, virtual particle / anti-particle pairs are constantly being "created"and "destroyed", so does the math allow for "collision" (changing the virtual / mathetical trajectory) between the virtual particle of pair A and the virtual particle of pair Bs, and does the math allow the virtual anti-particle from pair A to "destroy" the virtual particle from pair B?

In a manner of speaking, certainly. Various vacuum loop diagrams could be interpreted something like you describe. In the end it all just contributes to the picture of what the vacuum itself is though. As for interacting with normal particles, well they do this all the time, otherwise we would not know they existed. Even just two electrons scattering off each other exchange virtual photons, which are clearly interacting with the real electrons.

Perhaps I am not really understanding your question though.

edit: I scoured google images for a nice picture of some vacuum bubbles, but the best I found was this:

vacuum_renorm-main.jpg


The last diagram shows some vacuum bubble affecting the propagation of a (say) photon, which perhaps is something like what you are thinking about?
 
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  • #3
Thanks Kurros. That's exactly the info that I was looking for. It can be difficult to separate the real / virtual elements in what I read generally on the subject. It's great to have a perspective on a specific question.

Regards,

Noel.
 
  • #4
The vacuum bubble above was first calculated by Uehling ( E.A. Uehling, Phys. Rev. 48, 55 (1935)), also by Serber in same issue. In bound muonic and pionic atoms (where pions or muons replace an atomic electron), this is called vacuum polarization. This has been confirmed to high accuracy by measurement of the atomic transition energy level shifts of muonic and pionic x-rays. This correction can shift atomic energy levels by several percent.
 
  • #5
Thanks Bob. I'm afraid that your description is a big bit above my current knowledge level! Do you know of a lowbrow article / forum that I could use to help me get started?

Regards,

Noel.
 

FAQ: Do virtual particles interact?

1. What are virtual particles?

Virtual particles are particles that spontaneously appear and disappear in the quantum vacuum. They are not physical particles like those we observe in everyday life, but rather fluctuations in the energy field.

2. How do virtual particles interact?

Virtual particles do not interact in the same way as physical particles. They do not have a well-defined trajectory or measurable properties, but instead, they influence the behavior of physical particles through the exchange of energy and momentum.

3. Can virtual particles be observed?

No, virtual particles cannot be directly observed because they exist for such a short period of time and do not have a physical form. However, their effects can be observed in experiments, such as the Casimir effect, which demonstrates the influence of virtual particles on the behavior of physical objects.

4. Do virtual particles obey the laws of physics?

Yes, virtual particles still obey the laws of physics, including conservation of energy and momentum. They are simply a manifestation of quantum mechanics and do not violate any fundamental principles of physics.

5. Can virtual particles be created or destroyed?

Virtual particles are constantly being created and destroyed in the quantum vacuum. However, they cannot be created or destroyed at will, and their existence is governed by the laws of quantum mechanics.

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