THE STABILITY OF MATTER IN MAGNETIC-FIELDS

The proof of the stability of matter is three decades old, but the que stion of stability when arbitrarily large magnetic fields are taken in to account was settled only recently. Even more recent is the solution to the question of the stability of relativistic matter when the elec tron motion is governed by the Dirac operator (together with Dirac's p rescription of filling the ''negative energy sea''). When mag netic fi elds are included the question arises whether it is better to fill the negative energy sea of the free Dirac operator or of the Dirac operat or with magnetic field. The answer is found to be that the former pres cription is unstable while the latter is stable.