Are vacuum EM modes circularly polarized according to QED?

[Pet Scan]

I'm talking of the virtual EM modes of vacuum...

 

[Vanadium 50]

In what direction would you expect them to be polarized?

 

[Pet Scan]

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?

 

[PeterDonis]

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.