Grabiak, M; Müller, B; Greiner, W, *Exclusion of quasi-bound e*^{+} e^{-} states at MeV energies within the framework of QED,
Annals of Physics, vol. 185 no. 2
(1988),
pp. 284-300 .
**Abstract:**

*We give general arguments that no narrow quasi-bound e+ e- state can exist above 2me. We extend the virial theorem of QED to quasi-bound states and show that corrections due to renormalization and due to the fact that a resonance is not an energy eigenstate are small. A "magnetically bound" e+ e- state with energy above 2me would violate this extended virial theorem. © 1988.*