Ronald Anderson

Conventionality of synchronisation, gauge dependence and test theories of relativity

Abstract The formal and operational significance of the choice of clock synchronization in relativity is reviewed, along with the historical debate over the associated choice of the one-way speed of light. Kinematic test theories generalising special relativity are recast in a nonstandard synchronisation. In particular, the Mansouri-Sexl test-theory is generalised to avoid a conflict between its interpretation and its gauge choice. Corresponding adjustments to the interpretation of recent experimental tests of relativity are presented. A test-theory for local Lorentz invariance is derived for a noninertial observer in a space of arbitrary curvature using differential geometric techniques and the Frenet frame. The Sagnac effect in a ring laser is considered for bounding the parameters of this theory.

Quaternions and the heuristic role of mathematical structures in physics

One of the important ways development takes place in mathematics is via a process of generalization. On the basis of a recent characterization of this process we propose a principle that generalizations of mathematical structures that are already part of successful physical theories serve as good guides for the development of new physical theories. The principle is a more formal presentation and extension of a position stated earlier this century by Dirac. Quaternions form an excellent example of such a generalization, and we consider a number of the ways in which their use in physical theories illustrates this principle.

The Referees' Assessment of Faraday's Electromagnetic Induction Paper of 1831

Faraday’s discovery of electromagnetic induction in August 1831 has been recognized as one of his great achievements, as well as a discovery of immense importance in understanding electromagnetism. John Tyndall, one of Faraday’s early biographers, surmised that ‘this discovery of magneto-electricity is the greatest experimental result ever obtained by an investigator. It is the Mont Blanc of Faraday’s own achievements.’ Thomas Martin, the editor of Faraday’s laboratory notes, remarked that Faraday’s discovery of induction, ‘was one of the most important experiments in the history of physical science . . .’ The phenomenon Faraday had demonstrated was the generation of an electric current (‘electricity in motion’) in a wire forming a closed circuit by the change of the current in an adjacent wire as well as by the wire either being in the presence of a changing magnetic force or moving through a region of magnetic force. The effect provided the anticipated converse of Oersted’s demonstration in 1820 that an electric current produced a magnetic force. The importance of the phenomenon in the development of electromagnetism may be seen in the pivotal role it played in Maxwell’s dynamical approach to electromagnetism.

SU(4) Clebsch--Gordan coefficients for the formation of baryonium and exotic baryons

We give the SU(4) Clebsch–Gordan coefficients required for the formation of exotic hadronic states of the form (QQQQ) and (QQQQQ).

Exploring the mathematical and interpretative strategies of Maxwell's Treatise on Electricity and Magnetism

Abstract James Clerk Maxwells Treatise on Electricity and Magnetism forms one of the major scientific texts of the 19th century, describing the phenomena of electricity and magnetism and the interaction between them. The sources Maxwell acknowledged as the inspiration for his own approach were the Englishman Michael Faraday and his fellow Scotsman William Thomson (later Lord Kelvin). In the Treatise Maxwell presents an approach he maintains was equivalent mathematically to the well established Continental electromagnetism but focused on an action via a medium approach to electromagnetism and located within a British experimental tradition. Exploring these features reveals the Treatise to be in accord with other deep themes in Maxwells writings, which ground him intellectually and personally in the world of 19th century British Natural Philosophy.

The Crafting of Scientific Meaning and Identity: Exploring the Performative Dimensions of Michael Faraday's Texts

Texts bear traces of complex struggles. For scientific texts, issues to do with the meaning of words and their reference are often where such struggles occur. In texts too identity is fashioned in the social realm and texts are woven closely into human cognition. The focus on how texts function to produce meaning, characteristic of recent literary theory, provides remarkable resources for locating these features in scientific texts. The project sketched here in a preliminary manner seeks to bring such resources to bear on Michael Faradays writings and explores in Faradays rich and reflexive textual space his persistent concern to stabilize the meaning and reference of words as well as the less conscious subtle complexities associated with the production of meaning. Both weave closely into his scientific theorizing and fashioning of identity.

Balancing Necessity and Fallibilism: Charles Sanders Peirce on the Status of Mathematics and its Intersection with the Inquiry into Nature

An interest in Charles Sanders Peirce and pragmatist thought in general emerged in the United States in the middle of last century to exert a powerful influ- ence on a generation of American philosophers educated in the 1940s and 1950s, including Abner Shimony, whose thought is the occasion for this paper. Those threads in Peirces work related to developing a scientifically informed worldview and metaphysics were the natural influences on Abner and this paper will begin by briefly reviewing a number of these threads and their influences in his writings. This sets the scene for the main project of the paper, an earlier historical project on a related aspect of Peirces thought—his understanding of mathematics and its place in the description of nature. Mathematics was a foundational discipline for Peirce, one with qualities of necessity and certainty, features that stand in interesting con- trast and tension to Peirces view of an evolving nature which is governed by chance and our knowledge of which is always fallible and thus open to revision. Exploring these issues reveals deep background beliefs structuring Peirces thought. The paper concludes in the contemporary realm with the speculation that due to the scientific developments of the 20th century, aspects of Peirces work that formed a vision for

Electromagnetic decay widths for L=1, J/sup P/C=1/sup - -/ T baryonia

A mass spectrum for the J/sup P/C=1/sup - -/, L=1, T baryonium states in the 1--5 GeV region is presented within the framework of quantum chromodynamics. The potential-dependent coefficients are determined from known baryons and mesons. The electromagnetic decay widths are calculated for these states by extension of the Van Royen--Weisskopf technique.

Electromagnetic decay widths for L = 1 , J PC = 1 − − T baryonia

A mass spectrum for the J/sup P/C=1/sup - -/, L=1, T baryonium states in the 1--5 GeV region is presented within the framework of quantum chromodynamics. The potential-dependent coefficients are determined from known baryons and mesons. The electromagnetic decay widths are calculated for these states by extension of the Van Royen--Weisskopf technique.

Factorisation of Regge slopes for multi-quark hadrons

Using duality and the factorisation relationships between residues, the authors present general rules for expressing the Regge slopes of multi-quark hadrons without string loops in terms of those of the standard three-quark baryons and two-quark mesons.