  Haisch and Rueda have recently proposed a model in which the inertia of
charged particles is a consequence of their interaction with the
electromagnetic zero-point field. This model is based on the observation that
in an accelerated frame the momentum distribution of vacuum fluctuations is not
isotropic. We analyze this issue through standard techniques of relativistic
field theory, first by regarding the field A_mu as a classical random field,
and then by making reference to the mass renormalization procedure in Quantum
Electrodynamics and scalar-QED.
