I'm a layperson currently reading through Matt Strassler and on his website, he states, in relation to using positronium as an example of vacuum fluctuation effects:
The stronger force between the electron and positron makes it more common for virtual photons to be present
My background is based primarily on Griffith's Quantum Mechanics and Particle Physics texts, I also think I understand the basic application of simple harmonic oscillators as creation and annihilation operators.
I don't want to appear lazy, but of the several reasons I can think of to answer my question myself, I just don't know enough to say which of them is correct. For example, do the charges add energy to the field, or is there an interference effect between the electron and positron, if we treat them as wave packets?
I know that the number of virtual particles increases as we approach the source, but how this is related to force in the way described is not immediately clear to me.
Obviously, I am as confused as I am ignorant on this topic, my apologies.
Is it possible to answer my title question, at the level of basic QFT, or to refer me to a source that does so?