On Monday, August 26, 2019 at 9:18:50 PM UTC-6, Bruce wrote: > > On Tue, Aug 27, 2019 at 12:40 PM Jason Resch <[email protected] > <javascript:>> wrote: > >> On Mon, Aug 26, 2019 at 9:25 PM Bruce Kellett <[email protected] >> <javascript:>> wrote: >> >>> On Tue, Aug 27, 2019 at 10:35 AM Jason Resch <[email protected] >>> <javascript:>> wrote: >>> >>>> On Mon, Aug 26, 2019 at 7:32 PM Bruce Kellett <[email protected] >>>> <javascript:>> wrote: >>>> >>>>> On Tue, Aug 27, 2019 at 10:27 AM Jason Resch <[email protected] >>>>> <javascript:>> wrote: >>>>> >>>>>> These videos provide a good introduction: >>>>>> >>>>>> https://www.youtube.com/watch?v=X5rAGfjPSWE >>>>>> https://www.youtube.com/watch?v=fG52mXN-uWI >>>>>> >>>>>> Virtual particles are the basis of all particle interactions in QED, >>>>>> called the jewel of physics for having made the most accurate >>>>>> predictions >>>>>> of any physical theory. >>>>>> >>>>> >>>>> The trouble is that virtual particles are internal lines in Feynman >>>>> diagrams, and the Feynman diagrams are formed as a perturbation >>>>> expansion. >>>>> They have to be summed to make contact with physical processes. This puts >>>>> the status of virtual particles, as ontological entities, into >>>>> considerable >>>>> doubt. Ultimately, they are nothing but a calculational device, and >>>>> quantum >>>>> amplitudes can be evaluated without ever using Feynman diagrams, so >>>>> virtual >>>>> particles need never appear anywhere. >>>>> >>>>> >>>> But this "calculational device" (funny how many things are mere >>>> devices) predicts the lamb shift as well as the Casimir effect, to great >>>> accuracy. >>>> >>> >>> No, virtual particles do not predict the Lamb shift -- they are just an >>> aid to calculating terms in the perturbation expansion of the QED vertex >>> function. >>> >>> >> Is this answer in error? >> https://physics.stackexchange.com/questions/443186/lamb-shift-and-virtual-particles >> >> > > No, that seems to give the standard Feynman diagrams for radiative > corrections to the photon propagator. (I misremembered previously. > Radiative corrections to the vertex function are important for the > calculation of g-2 for the electron, not for the Lamb shift, which is a > photon propagator correction.) But the standard calculation says nothing > about reifying the internal lines in the diagrams. In fact, a good > approximation to the Lamb shift can be obtained from a simple > non-relativistic calculation that never mentions quantum fields, vacuum > polarisation, or virtual particles. > > Aren't virtual particles necessary for explaining the limited range of the >> strong force? >> > > No. The uncertainty principle can do that. > > >> And solving the blackhole information paradox? >> > > No. There is no BH information paradox, and virtual particles are not > necessary in order to understand Hawking radiation (despite what Hawking > says in his popular accounts. His original paper on the matter does not use > virtual loops. Not that these exist in the way described, anyway.) > > Bruce >
Your objections to reifying virtual particles seems very well founded. Despite that, in your opinion is there a consensus in the physics community that they exist? Remember, the existence of the quantum foam is the necessary condition for the conjecture that the Cosmos arose as a quantum perturbation or eruption from that foam. AG -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/everything-list/99ed9d9d-9acc-4d87-8ca1-4d084259863b%40googlegroups.com.
