Answers are grounded in this paper and cite their sources.
It has been found recently that the vacuum state of quantum electrodynamics (QED) is infinitely degenerate. The authors exploit this fact and show that any non-trivial scattering process in QED is necessarily accompanied by a transition among the degenerate vacua, making the scattering amplitude finite at low energy scales (infrared finite).
No takes yet. Share an insight, caveat, or question.
Kapec et al. (2017) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: