Are vacuum EM modes circularly polarized according to QED?

In summary, the conversation discusses the polarization of virtual photons in the vacuum and whether or not they can have circularly polarized modes. It is argued that since the vacuum has no preferred direction, it is not possible for virtual photons to be polarized.
  • #1
Pet Scan
27
1
I'm talking of the virtual EM modes of vacuum...
 
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  • #2
In what direction would you expect them to be polarized?
 
  • #3
How can I expect a direction when I don't even know if it is possible for Virtual photons to have circularly polarized modes? In other words; are the fundamental vacuum EM virtual modes circular polarized (like real photons) ? IOWs, in vacuum does QED take into account a virtual photon's circularly polarized state?
 
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  • #4
Pet Scan said:
How can I expect a direction when I don't even know if it is possible for Virtual photons to have circularly polarized modes?

You've missed the point @Vanadium 50 was making. For any EM mode to be polarized, it must be polarized in a particular direction. That means that particular direction is different from other directions. But in the vacuum, all directions are the same; they have to be, because it's vacuum, so there is nothing there to pick out a particular direction. So virtual photons in the vacuum can't be polarized, because if they were, it would violate the property of the vacuum that all directions are the same.
 

FAQ: Are vacuum EM modes circularly polarized according to QED?

1. What is QED?

QED stands for Quantum Electrodynamics. It is a theory that describes the interactions between electromagnetic radiation and matter at the quantum level. It is considered to be one of the most successful theories in physics.

2. What are vacuum EM modes?

Vacuum EM modes are the different possible ways in which electromagnetic fields can exist in a vacuum. They are described by the strength and direction of the electric and magnetic fields.

3. Are vacuum EM modes circularly polarized?

Yes, according to QED, vacuum EM modes can be circularly polarized. This means that the electric and magnetic fields rotate in a circular pattern as the electromagnetic wave travels through space.

4. How is circular polarization determined in vacuum EM modes?

Circular polarization in vacuum EM modes is determined by the direction of the electric field vector. If the electric field vector rotates in a clockwise direction, the mode is considered to be right circularly polarized. If it rotates in a counterclockwise direction, it is considered to be left circularly polarized.

5. What are the implications of vacuum EM modes being circularly polarized according to QED?

The circular polarization of vacuum EM modes has important implications in various areas of physics, such as quantum optics and quantum information processing. It also helps to explain certain phenomena, such as the polarization of light from distant sources in the universe.

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