Are vacuum EM modes circularly polarized according to QED?

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    Em Modes Qed Vacuum
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Discussion Overview

The discussion revolves around the nature of virtual electromagnetic (EM) modes in vacuum, specifically whether these modes can be circularly polarized according to quantum electrodynamics (QED). Participants explore the implications of polarization in a vacuum context, questioning the existence and characteristics of virtual photons.

Discussion Character

  • Debate/contested

Main Points Raised

  • Some participants inquire about the possibility of virtual photons having circularly polarized states, similar to real photons.
  • Others argue that for any EM mode to be polarized, it must have a specific direction, which contradicts the isotropic nature of vacuum where all directions are equivalent.
  • A participant emphasizes that if virtual photons were to be polarized, it would violate the fundamental property of the vacuum, suggesting that virtual photons cannot be polarized.

Areas of Agreement / Disagreement

Participants express differing views on whether virtual photons can possess circular polarization, with some asserting it is impossible due to the nature of vacuum, while others question the assumptions underlying this claim. The discussion remains unresolved.

Contextual Notes

The discussion highlights the dependence on the definitions of polarization and the properties of vacuum, as well as the unresolved nature of virtual photon characteristics in QED.

Pet Scan
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I'm talking of the virtual EM modes of vacuum...
 
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In what direction would you expect them to be polarized?
 
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?
 
Last edited:
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.
 

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