THE scope of this book is indicated by the fact that it is based on lectures to honours physics students, and the treatment by the fact that it follows the lines of Prof. Dingle's recent contributions in NATURE. The interest provoked by the latter may justify the length of the present notice. The Special Theory of Relativity By Prof. Herbert Dingle. (Methuen's Monographs on Physical Subjects.) Pp. vii + 94. (London: Methuen and Co., Ltd., 1940.) 3s. 6d. net.

The Special Theory of Relativity

From Classical to Relativistic Mechanics: Electromagnetic Models of the Electron

We discuss an article by Le Bellac and Levy-Leblond in which they have identified two Galilean limits of electromagnetism (1973 Nuovo Cimento B 14 217–33). We use their results to point out some confusion in the literature, and in the teaching of special relativity and electromagnetism. For instance, it is not widely recognized that there exist two well-defined non-relativistic limits, so that researchers and teachers are likely to utilize an incoherent mixture of both. Recent works have shed new light on the choice of gauge conditions in classical electromagnetism. We retrieve the results of Le Bellac and Levy-Leblond first by examining orders of magnitudes and then with a Lorentz-like manifestly covariant approach to Galilean covariance based on a five-dimensional Minkowski manifold. We emphasize the Riemann–Lorenz approach based on the vector and scalar potentials as opposed to the Heaviside–Hertz formulation in terms of electromagnetic fields.

On the electrodynamics of moving bodies at low velocities

It is well recognized that two of the foundational theories of modern physics, relativity and quantum mechanics, are inconsistent. Efforts to overcome this through intensive pursuit of unifying theoretical frameworks or improvements in experimental precision as pursued by Robertson-Mansouri-Sexl and Standard-Model-Extension test theory protocols, have so far proven unsuccessful. Nonetheless, empirical evidence deriving from investigations inspired by the twentieth-century “EPR” polemic, can now claim to have identified ‘locality’ and ‘separability’ as notions integral to special relativity theory inconsistent with quantum mechanics and experimental evidence supporting it. Following intimations of J.S. Bell, L. Smolin, Maudlin and others, the history and philosophy of science are engaged as research tools to uncover the origins of the assumptions underlying such incompatibility. In particular, known but prevalent fallacies and the deprecation of processes as described by Whitehead, together with recent insights into the functional distinctions between representative models and explanatory theories, are engaged. Analysis of the evolution of optical and electromagnetic theorizing is then suggested to demonstrate that the choice of a mechanically compatible model of electromagnetic radiation, as has conventionally underwritten development of the light-speed postulate of special relativity, is inappropriate. Pursuing options made available within a multiple models idealization of optical and electromagnetic phenomena, replacement of the sponsoring model by a nonlocal and non-separable wavefront process of radiation of the form advanced by Fresnel and Kirchhoff on the basis of Huygens’ principle, suggests the possibility of reformulation of relativity theory without incurring such conflicts. However, choice of a wavefront electrodynamic model including the extinction theorem of Ewald and Oseen, equally suggests possible theory reformulation without necessitating a four-dimensional construct of space and time or postulating an absolute constancy of light-speed in vacuum. Such a constancy can in turn be considered as demonstrating an innate limitation on empirical observation resulting from the loss of relative velocity information during electromagnetic transmission due to the memorylessness of the Markov propagation process of refraction together with information flow discontinuity resulting from dielectric boundary extinction events. Such characteristics are shown to be applicable to electromagnetic radiation of all frequencies. Further, from a wavefront reformulated hypothesis of inertial relative motion, it appears possible to demonstrate that the Galilean principle of relativity can be preserved. However, Lorentz invariance would then require reinterpretation wherein the Lorentz transform group would be deemed to quantify the degree of information distortion inherently experienced by any empirical enquiry into electrodynamics involving relative motion.

https://researchbank.swinburne.edu.au/file/261593b6-a3e7-4ddb-b042-8ceec25d1838/1/Gareth Boardman Thesis.pdf

An information theory interpretation of relativistic phenomena

We discuss the seminal article by Le Bellac and Levy-Leblond in which they identified two Galilean limits (called “electric” and “magnetic” limits) of electromagnetism and their implications. Recent work has shed new light on the choice of gauge conditions in classical electromagnetism. We show that the recourse to potentials is compelling in order to demonstrate the existence of both (electric and magnetic) limits. We revisit some nonrelativistic systems and related experiments, in the light of these limits, in quantum mechanics, superconductivity, and the electrodynamics of continuous media. Much of the current technology where waves are not taken into account can be described in a coherent fashion by the two limits of Galilean electromagnetism instead of an inconsistent mixture of these limits.

https://hal.archives-ouvertes.fr/hal-00082058/PDF/GalEDHAL.pdf

On some applications of Galilean electrodynamics of moving bodies

In this paper we try to disentangle the development of two connected strands of thought, associated respectively with Maxwell and Poincare, so as to throw light on several questions connected with the special theory of relativity. For example, who first used the word 'relativity' in physics in the sense we understand it today, meaning: in all physical experiments, whether mechanical or electromagnetic, only the relative velocity of a body can be measured, i.e. the notion of velocity of a body as such is a concept without physical importance? Which was the earliest experiment undertaken to determine the absolute motion of the earth through the hypothetical ether or space, if such putative motion had a physical consequence at all, and by whom ? In short, what exactly were the contributions of various physicists before the publication of Einstein's monumental contribution of 26 September 1905 submitted for publication to Annalen der Physik on 30 June 1905? While we were writing this paper, our attention was drawn to the highly illuminating discussion given by Miller [1981]. We have been able to use Miller's discussion to improve the paper; but his objective is not the same as ours.

C. W. Kilmister

Papers

Intimations Of Relativity Relativity Before Einstein