Conservation of energy and momentum for an electromagnetic field propagating into a linear medium from the vacuum

Abstract

The form of the energy-momentum tensor when a quasimonochromatic field propagates into and through an antireflection-coated, sourceless, transparent, continuous, linear magneto-dielectric medium, initially at rest in the local frame, remains controversial. The Minkowski energy-momentum tensor is the main component of the electromagnetic conservation law. It has been known for over a century that the electromagnetic conservation law is unsound as evidenced by alternative energy-momentum tensors that have been proposed to ameliorate known physical deficiencies (violation of conservation of angular and linear momentum) and by the various material energy-momentum tensors and coupling forces that have been introduced to repair or complete the law. The extant resolution is to treat the continuum electromagnetic system as a subsystem and add a phenomenological material subsystem energy-momentum tensor. We show that the four-divergence of the total, electromagnetic plus material, energy-momentum tensor produces an energy continuity theorem in which the two non-zero terms depend on different powers of the refractive index $n$. Then the extant resolution of the Abraham-Minkowski controversy is self-inconsistent.