Livre : mécanique quantique cours et exercices corrigés
Description :
An extremely neat, clear, thorough, tersely written monograph on a subject not only of great practical importance, but above all of great aesthetic charm, the coherence properties of optical waves. Most of these properties appear in classical approximation, but the quantization of the field intro- duces some finer features well worth studying; the more so as the detection technique (by photoelec- trons, for instance) is based on atomic processes of essentially quanta1 nature. In this book, both the classical and the quanta1 treatments are fully developed; the exposition is selfcontained; all auxiliary concepts, such as the interesting “coherent states”, are discussed from first principles. In a future edition, formal blemishes might be removed: the recommended unit symbols ought to be used (thus Hz instead of “cycle per second”) and the horribly sounding”Markofian” corrected to “Markovian”.
Knowing van ‘t Hoff’s forceful personality, one turns with curiosity to a reprint (were it only a translation) of his practically unknown inaugural discourse of 1878 on a subject of perennial interest. One’s expectations are, alas, disappointed. The 26-year old chemist had already given evidence of his uncommon gift of creative imagination by proposing to interpret physico-chemical properties of organic molecules on the basis of the spatial arrangement of the constitutive atoms. This idea stag- gered the chemical authorities of the time, and even prompted the foremost of them, Kolbe, to write a virulent criticism of it, strikingly illustrating the peculiar resistance opposed to rational imaginative thinking by chemists skilled in empirical manipulations. In his inaugural discourse, van ‘t Hoff saw his opportunity of retorting Kolbe’s ungenerous and shortsighted attack, and he could not fail to make some judicious, though hardly novel, observations on the role of imagination in furthering scientific investigation. The greatest part of the discourse, however, is devoted to showing that great scientists also display imagination in the form of literary or artistic interests, or even on the pursuit of bizarre fixations and fancies verging on insanity! To make things worse, he draws information in support of this thesis from second-hand and quite unreliable sources, such as Arago’s and Cuvier’s biographies, which he excerpts and quotes at length with incredible naivete. It was not, therefore, a particularly happy idea to revive this trifling piece; and to spoil it by an incompetent and careless translation is simply outrageous.
This publication from 1960, of which we are now given both a French and an English translation, marks the happy ending of an extraordinary episode in the history of quantum theory - an episode comparable to the opposition of the Jesuits in the XVIIth and XVIIIth centuries to the growth of the spirit of free enquiry fostered by the expansion of science. Misled by an insufficiently discrimi- nating use of dogmatic preconceptions, the Russian physicists - with the exception, of course, of an elite inspired by such men as Landau and Tamm - remained for thirty years blind to the evidence of complementarity. At long last, they have seen the light. Just as the Jesuits, when they realized the futility of their ostracism of the Copernican system, far from acknowledging defeat, started to build observatories and promote Copernican astronomy as if they had never done anything else - they would now make us believe that complementarity is better understood in Dubna than it ever was in Copenhagen. This all too human weakness will gladly be forgiven them, however, for the main thing
in science is agreement on the objective state of affairs, and on this basis our Russian fellow-workers are now enabled to contribute to epistemology as fruitfully as to other aspects of physics. Professor Blokhintsev’s book is indeed an example of what we may expect from their active parti- cipation to the common effort. Written with literary distinction and refreshing humour, it contains a clear and thoughtful discussion of the essential epistemological points of atomic physics, illustrated with well-chosen and mostly original examples, treated very thoroughly. He aptly characterizes the Feynman formalism as a use of “non-observable hidden parameters”; although he does not make the full implication of this very explicit, I hope it will not escape the attentive reader.
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