← Back to context

Comment by bowsamic

3 years ago

Actually the basic particle created by the creation operator for a mode is totally delocalised. Applying the field operator to get a localised particle is really an integral over many particles

For a free field, yes. But the entities we actually interact with are ... interacting. Mode expansion doesn't work here. Electrons, photons, etc. aren't really "particles" in the sense of ordinary quantum mechanics at all.