NEGATIVE-ENERGY DENSITY AND CLASSICAL ELECTRON MODELS

We discuss the fact, pointed out by Bonnor and Cooperstock, that the electron, modelled as a spherically symmetric charged distribution of matter (in the context of general relativity), must contain some negative rest mass if its radius is not larger than 10(-16) cm. Analysing some extended electron models, we show that negative energy density distributions result from the requirement that the total mass of these models remains constant in the limit of a point particle.