The discussion centers on the nature of virtual particles and their interactions, particularly in the context of quantum field theory (QFT) and the cosmological constant. Participants debate whether virtual particles can interact with each other, with some asserting that they are merely artifacts of perturbation theory and not real entities. The conversation also touches on the implications of vacuum energy on cosmic expansion and the confusion surrounding the role of virtual particles in Hawking radiation. Key references include Dyson series and the works of John Baez, emphasizing the need for precise language in discussing these concepts.
PREREQUISITESPhysicists, students of quantum mechanics, and anyone interested in the foundational concepts of quantum field theory and cosmology.
friend said:Of course they're not defined as observables, since they are virtual. I think the problem is that virtual particles are not defined, even for the brief moment they might appear, to have a specific location in time and space. So things like trajectory are not applied to them. But perhaps the probability of virtual particles interacting is calculable. Isn't that what we are doing inside complicated Feynman diagrams?