On continuum dynamics and the electromagnetic field in the scalar ether theory of gravitation

Abstract: We summarize a recent work on the title subject, skipping the detailed calculations but introducing the basic points with enough detail. The theory considered is formulated in a preferred reference frame in a four-dimensional spacetime endowed with a curved "physical" metric. The dynamics of a test particle is defined by an extension of the special-relativistic form of Newton's second law. This determines the dynamical equation verified by the energy-momentum tensor ${\bf T}$ of a "dust" continuum, also in the presence of a non-gravitational external force. The dynamical equation for ${\bf T}$ thus obtained is assumed valid for a general continuous medium or a system of fields. When the non-gravitational force is the Lorentz force, this equation in turn determines the Maxwell equations in a gravitational field for the present theory. They are consistent with the dynamics of photons i.e. with the geometrical optics of the theory. Except for a constant gravitational field, they seem to imply some local production or destruction of electric charge. The possible amounts are yet to be assessed.