Text Size
Facebook Twitter More...

Real particles are poles of the Feynman propagators in the complex energy plane that obey the mass shell equation

E^2 = (pc)^2 + (mc^2)^2

(Pythagorean theorem)

VIrtual particles like zero point vacuum fluctuations are "off shell" and do not obey the above equation.

Virtual fermion-antifermion pairs (isolated closed loop Feynman diagrams for spin 1/2) have positive zero point vacuum pressure and act as dark matter.

So do the Faddeev-Popov ghosts, i.e. spin 0 with anti-commutation rules like tachyons.
Category: Science