Hendrik Casimir

Abstract

In the literature of physics Hendrik Casimir features amongst a multitude of names associated with Laws and Effects, each name a convenient label for a precise physical relationship of one kind or another. Such names generally connote the provenance of the scientific principles they convey, usually identifying the individual or individuals accredited with the first public pronouncement or publication. The history of science is of course replete with examples of how societal criteria have borne upon the attachment and acceptance of such names, especially where the science has been the subject of more than one individual's work. However this is not so in the case of Casimir, whose ground-breaking work on microscopic forces has been granted eponymy unequivocally. To mark the sad news of his death last year, this special section of European Journal of Physics celebrates the discovery, underlying principles and implications of Casimir forces, together with a biographical sketch that helps illustrate the man's much wider sphere of scientific influence. In publications that spanned 45 years his research output covered an astonishing range of topics in physics, and in a sense the necessary focus here on one particular branch of his work does a necessary disservice to the whole. Nonetheless there are special reasons for focussing on his work on microscopic forces, because of their highly significant implications for the foundations of physics. The experimental verification of the results Casimir obtained has been widely interpreted as vindicating some of the most important but least intuitive principles of quantum electrodynamics, the progeny of quantum mechanics and special relativity.Casimir was a man highly interested in the communication of science at all levels, from conferences to magazines for the general public, and with a genuine interest in science-related philosophical issues. A popular speaker at both formal and informal occasions, he was also a keen and able writer, serving for several years on the Editorial Board of the Dutch literary magazine De Gids. Within and beyond the Philips organisation Casimir actively promoted European collaboration in science; he also increasingly directed efforts towards the advancement of professional standards in research management. With all these interests and activities, and also as a former President of the European Physical Society (under whose auspices this journal is published) it is particularly appropriate to mark his passing with the publication of this commemorative section of European Journal of Physics. It has been my great pleasure and honour to be involved. I would like to thank all who have contributed to the special papers for this issue. I am especially pleased to acknowledge very helpful communications with the Philips organisation, and in particular Lou-Fe' Feiner, whose enthusiasm for this project afforded me valuable personal recollections and many other useful insights. For further information the interested reader will undoubtedly appreciate reading Casimir's autobiography Haphazard Reality. Half a Century of Science 1983 (New York: Harper and Row).Note added in proof: As this edition was going to press, news also emerged of the recent death ofDik Polder, whose collaboration with Casimir led to some of the key resultscelebrated in this issue. It is fitting to record his importantcontributions to the work, and to extend tribute to a man whose name willremain inextricably linked with Casimir's.