AE Shabad & VV Usov contended in a number of papers that a large-enough magnetic field would create pairs because the positronium "atom" would be compressed by the magnetic field, and then have an arbitrarily negative Coulomb energy. http://arxiv.org/abs/hep-th/0605020 http://arxiv.org/abs/astro-ph/0601542 http://arxiv.org/abs/hep-th/0603070 http://arxiv.org/abs/hep-th/0512236 Their results were happily used in http://arxiv.org/pdf/astro-ph/0610441v2.pdf and at least 20 other papers continuing thru year 2014. Meanwhile CN Leung & S-Y Wang claimed to have refuted all that: http://arxiv.org/abs/0901.3413 (All papers refereed, published, etc.) Who is right? I do not find ANY of these convincing/understandable. The alleged exact solution of a hydrogenic atom in a magnetic field by CC Bernido, NS Lim, MV Carpio-Bernido (1996) http://streaming.ictp.trieste.it/preprints/P/96/231.pdf [energy levels on page 8; later apparently published as C.C. Bernido, M.V. Carpio-Bernido and N.S. Lim: "Sum-Over-Histories for the Dirac Electron of a Hydrogenic Atom in Superstrong Magnetic Fields," in Frontiers in Quantum Physics, eds. S.C. Lim, R. Abd-Shukor, K. H. Kwek (Springer-Verlag, Singapore, 1998) p. 251. ] seems however to flat out contradict the claims of Shabad+Usov about the positronium "atom" and was cited by none of those papers, despite all of them coming way after 1996. Apparently theoretical physics is a write-only field, and any claim is ok. -- Warren D. Smith http://RangeVoting.org <-- add your endorsement (by clicking "endorse" as 1st step)