Causes Virtual Particles or Vacuum Energy or Other?

[rchase]

I understand the basics of the double slit experiment.
I'm trying to imagine what would happen if one slit could operate at a 180 degree phase shift, or nearly that. The obvious answer is not much except between the slits, and even less if the distance between the slits is near the wave length.
(Note if one slit operated at 180 phase shift and spaced a n-wave lengths from the first slit, it would be targeted to completely destroy the other wave, but produce a 'virtual' wave front of nothing.)

My question is: Do the photons still exist despite not much happening (elecromagnetically)?
A step further: Do photons which are canceled by another slit gone, or do they contribute to the virtual particles or vacuum energy or something like that?

Far out question: Could we control the force on a casimir plate sensor?

I know there are some interfered photons. My question is about the things we can't see, are there more missing photons all around us which can't be recovered? Can we setup an emitter which emits an entirely canceled wave. If so, is there a sea of photons which are essentially summing to zero. And if so, how does this affect vacuum energies and virtual interactions, or gravity for that matter...

 

[azntoon]

The answer to your questions is yes. Photons that are canceled out by the 180 degree phase shift still exist, but they do not interact electromagnetically with other photons. The effect of their existence is that they contribute to the virtual particles and vacuum energy. If two waves of equal amplitude and opposite phase are produced, then their effect will be to produce what is known as a "destructive interference" pattern in which the electromagnetic fields cancel each other out. This has an effect on the force on a Casimir plate sensor, as it decreases the overall force due to the canceling of waves. In terms of the sea of photons, yes, there can be photons that sum to zero and these are referred to as "virtual photons". These virtual photons play an important role in quantum field theory, contributing to vacuum energy and virtual interactions. As for their effect on gravity, this is still an open question and is an area of active research.