2 ms·
No, it's a pretty well-defined concept when you stick to its technical definition as an aid in interpreting terms of a perturbation series as Feynman diagrams.
by nimish 4y ago
No, it's a pretty well-defined concept when you stick to its technical definition as an aid in interpreting terms of a perturbation series as Feynman diagrams.
> these other excitations do have real observable effects
Yeah, that's the major thing: virtual particles explain observable effects in a sort-of intuitive way.
But you could (to my knowledge) get the exact same results without involving any virtual particles, via lattice gauge theory. Since you get the same observable results without them, virtual particles, IMO, shouldn't be considered fundamental to any effect, even if they make the explanation a lot easier.
Anything involving complicated interactions with relativity like Hawking-Unruh stuff has an even bigger issue since the notion of a particle/vacuum is observer dependent.
- l33tman 4y agoAll post-classical effects in quantum field theory arise from various "corrections" that come from what you could define as virtual particles, whether it's from the perturbative treatment or a numerical lattice gauge calculation. In the latter, you need to (formally) sum over all possible field configurations, the majority of which will contain half-witted weird off-shell "particles" and the entire spectrum between stuff you'd never see as a particle and the classical resonances. It is more clearly visualized in a perturbative expansion, for sure, but it's a bit disingenous I think to argue that there are no virtual particles in a lattice calculation.