Do Virtual Particles Really Exist in Our Universe?

[Rouge72]

You won't get a much better answer than what I already gave you in #15. FTL speeds are definitely included in the calculation, but there's no good reason to think that something is actually traveling along the paths in spacetime that contribute to the final result.

is there evidence or proof for the existence of virtual particles?

 

[SpectraCat]

is there evidence or proof for the existence of virtual particles?

Check out "The universe in a nutshell" by Stephen Hawking. Or just google the "Casimir effect". There have been attempts to measure "vacuum fluctuations", or the "zero point energy", by measuring tiny forces between uncharged metal plates in vacuum. One proposed qualitative, phenomenological explanation of these effects is that they arise because the plates create a cavity, thereby restricting the frequencies of the virtual particles that can pop into existence between them. One can show this more formally using Feynman diagrams with virtual particles, as is done in many texts.

However, it should definitely be noted that alternative explanations of the effect in terms of relativistically retarded van der Waals forces arising from the charged particles moving inside the conductors have also been demonstrated. (see http://arxiv.org/PS_cache/hep-th/pdf/0503/0503158v1.pdf)

So, while the Casimir effect is consistent with the existence of virtual particles, it evidently does not require them.