Does virtual particle-antiparticle annihilation produce anything?

[kdlsw]

My understand is, the virtual particle-antiparticle pairs created under uncertainty principle are not the same as the traditional particle-antiparticle (creates new particle after annihilation), the virtual ones does not produce anything, since they are created from nowhere, which the antiparticle must have exact but opposite (negative) energy as the particle.

Please correct if my understanding is not right. Thanks

 

[Simon Bridge]

The virtual particle-antiparticle pairs are understood as fluctuations in vacuum energy - the Feynman diagram shows a photon in and a photon out with the pair in a single loop between them.

The thing about virtual particles is that they are virtual - think of them as steps in a calculation and things should settle down for you. Their presence in the math represents a probability of an interaction.

 

[ChrisVer]

Let's talk for electron and positron...
they create the real photon... you can see the pair of particle antiparticle in analogy to how you see a virtual photon being emitted and reabsorbed .. In the photon's case you have a bosonic propagator which, in the qft formalism, you integrate over all possible momenta. In the case of a photon creating a pair of virtual electron+positron, you deal with is as a fermionic propagator, which has different form, but still the idea is the same. All these correspond to several possible loops which exist in Feynman's diagrams...
All this as an additional comment to Simon's post #2...