Let's take a look at the quantum vacuum (which, on closer inspection is not faithful as it shows constant periodic behavior):
There surely is something going on. Now I don't want to speak about the reality of virtual particles, as both sides in this debate are defensible.
No, I want to get some information about the nature of time in this whirling world of colors (if we should believe our eyes...). Does a virtual particle travel forward as well as backward in time, the backward traveling part representing anti-particles? A virtual particle carries a wide spectrum of energies and 3-momenta, which are independent from one another as the virtual is not on mass-shell. But what about time? If we take another look at the dizzying image, process doesn't seem to go forward nor backward in time. Or both at the same time. Can we somehow see this in the expression for the virtual particle?
To be clear, I don't ask about the reality of virtual particles. That's a question we could argue about endlessly. No, I'm asking if we can say anything sensibly about the direction in time virtual particles travel in. If their mathematical description can inform us. I can remember reading they fluctuate in time.
This question comes close but doesn't answer mine.
