"virtual photons" . "virtual particle\u2013antiparticle pairs" . "Virtual particle" . "virtual quark" . "Virtual particle#Pair production" . "virtual photon" . . . . . "virtuality of the photon" . "\\\"virtual\\\" particle" . . "vacuum fluctuations" . . . "Virtual particle" . "virtual_particle" . "virtual particle-antiparticle pair" . "virtual particles" . . "virtual" . "virtual particle" .