New perspectives on the relevance of gravitation for the covariant description of electromagnetically polarizable media

Abstract

By recognising that stress-energy-momentum tensors are fundamentally related to gravitation in spacetime it is argued that the classical electromagnetic properties of a simple polarisable medium may be parameterised in terms of a constitutive tensor whose properties can in principle be determined by experiments in non-inertial (accelerating) * E.mail: tdereli@ku.edu.tr † E.mail: j.gratus@lancaster.ac.uk ‡ E.mail: r.tucker@lancaster.ac.uk 1 frames and in the presence of weak but variable gravitational fields. After establishing some geometric notation, discussion is given to basic concepts of stress, energy and momentum in the vacuum where the useful notion of a drive form is introduced in order to associate the conservation of currents involving the flux of energy, momentum and angular momentum with spacetime isometries. The definition of the stress-energy-momentum tensor is discussed with particular reference to its symmetry based on its role as a source of relativistic gravitation. General constitutive properties of material continua are formulated in terms of spacetime tensors including those that describe magneto-electric phenomena in moving media. This leads to a formulation of a self-adjoint constitutive tensor describing, in general, inhomogeneous, anisotropic, magneto-electric bulk matter in arbitrary motion. The question of an invariant characterisation of intrinsically magneto-electric media is explored. An action principle is established to generate the phenomenological Maxwell system and the use of variational derivatives to calculate stress-energy-momentum tensors is discussed in some detail. The relation of this result to tensors proposed by Abraham and others is discussed in the concluding section where the relevance of the whole approach to experiments on matter in non-inertial environments with variable gravitational and electromagnetic fields is stressed.MSC codes: 83D05, 83C40, 83C35

Evaporating Black-Holes, Wormholes, and Vacuum Polarisation: Must they Always Conserve Charge?

“…Of course, when considering the total momentum, i.e. that of the electromagnetic field plus that of the response of the medium, one encounters the thorny issue of the Abraham-Minkowski controversy [33,34] and choice of Poynting vector [35]. From the perspective here, the question of which momentum is most appropriate would be further complicated by the non existence of the excitation 2-form.…”

Non-minimal ln (R)F 2 couplings of electromagnetic fields to gravity: static, spherically symmetric solutions

“…We can further introduce the polarization 1-form p ≡ d − e = (Y − 1)ι U F and magnetization 1-form m ≡ b − h = (1 − Y )ι U * F relative to a time-like unit velocity vector field U of an inertial observer ( For more details see [19][20][21]). …”

Observation of a Push Force on the End Face of a Nanometer Silica Filament Exerted by Outgoing Light

“…In a transparent dielectric of refractive index n, Minkowski suggested for the momentum of light [3], whereas Abraham suggested for the same physical quantity [4], where c nE / ) /(nc E E and c are the energy and vacuum speed of light respectively. There are a significant number of irradiative theories to clarify these two momenta [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22], the number of experimental tests are, however, far less [23][24][25][26]. One of the experimental tests observing the radiation pressure at the water-air interface [23] is now reckoned to support Abraham momentum [2].…”