A pictorial approach to macroscopic space-time symmetry, with particular reference to light scattering

Abstract

The physical nature of the constraints imposed on a macroscopic system in equilibrium by space-time symmetry, in order for it to exhibit a particular effect, can be readily determined from a pictorial display of the relevant experiment and of its space- and time-transformed versions. No knowledge is required of the structure of the system, or of the transformation behaviour of the property tensors responsible for the effect. The method is illustrated with reference to two known effects in crystals and then applied to a systematic analysis of light scattering by a fluid for a variety of incident and scattered polarization states, both in the absence and presence of an applied field. A range of new light scattering experiments is suggested. Among these are circular intensity differential effects which are induced by, and linear in, an applied electric or magnetic field, and which differ from previously described effects in that the scattered intensity is analysed for its +45$^\circ$ and -45$^\circ$ linearly polarized components, instead of, as before, its 0$^\circ$ and 90$^\circ$ components.