Quantized Field Theories and the Principle of Reciprocity

Abstract

THE quantum theory of wave fields (reviewed by Pauli¹ in 1941) shows it is possible, starting from a known Lagrangian function L, to calculate the charge-current vector, the energy-energy flux tensor, and the angular momentum tensor for any wave field, and further how to quantize the field in such a way that the charge, energy and momentum of the field are expressed as integral multiples of some elementary units which are associated with the constituent particles of the field. The theory has recently been extended by Chang² and de Wet³ to a more general type of Lagrangian, involving any number of space and time derivatives of the wave vector ; the calculations of these authors are, however, so complicated that it is difficult to see how they could be applied, even if any specific application were envisaged, and besides they do not fully satisfy the requirements of relativity.