Non-localizability of electric coupling and gravitational binding of charged objects

Abstract

The energy–momentum tensor in general relativity contains only localized contributions to the total energy–momentum. Here, we consider a static, spherically symmetric object consisting of a charged perfect fluid. For this object, the total gravitational mass contains a non-localizable contribution of electric coupling (ordinarily associated with electromagnetic mass). We derive an explicit expression for the total mass which implies that the non-localizable contribution of electric coupling is not bound together by gravity, thus ruling out the existence of objects with pure Lorentz electromagnetic mass in general relativity.