Generally covariant Maxwell theory for media with a local response: Progress since 2000

Abstract

Abstract-In the recent decades, it became more and more popular for engineers, physicists, and mathematicians alike to put the Maxwell equations into a generally covariant form. This is particularly useful for understanding the fundamental structure of electrodynamics (conservation of electric charge and magnetic flux). Moreover, it is ideally suited for applying it to media with local (and mainly linear) response behavior. We try to collect the new knowledge that grew out of this development. We would like to ask the participants of EMTS 2016 to inform us of work that we may have overlooked in our review. If the medium has a local and linear response behavior, the excitation H = (H, D) is local and linear in the field strength F = (E, B). In components we havěHere i, j, ... = 0, 1, 2, 3 andȞ ij := (1/2)ǫ ijkl H kl . The response tensor density χ has 36 independent components. It can be decomposed into three irreducible pieces with 36 = 20 + 15 + 1 components, respectively. Split in (1+3) dimensions, with a, b, .. = 1, 2, 3, we have (for details, see [18], [24])Up to here, the metric of spacetime, that is, the gravitational potential, did not enter anywhere. We have a premetric B D