The author begins by recalling how he was led in 1923–24 to the ideas of wave mechanics in generalizing the ideas of Einstein's theory of light quanta. He made himself at that time a concrete physical picture of the coexistence of waves and particles and, in 1927, attempted to give them precise form in his “theory of the double solution.” As other ideas prevailed at the time, he abandoned the development of his conception. But for the past twenty years, once (...) again convinced, like Einstein, that present-day quantum mechanics is only a statistical theory and does not give a true picture of physical reality, he has again taken up his old ideas and developed them considerably. He has in particular introduced an element of randomness into the theory and has thus attained to a “hidden thermodynamics of particles,” the results of which appear to be very interesting. (shrink)

Now, this is precisely the experimental law of the photo-electric effect in the form which has been verified in succession for all the radiations from the ultra ...

Cet ouvrage offre aux lecteurs une série de monographies consacrées presque toutes à diverses questions de Physique quantique et de Mécanique ondulatoire. Cet ensemble d'essais étudie l'aspect vraiment nouveau que prennent dans la Physique de l'époque le traditionnel dilemme « continu ou discontinu », la classique opposition de l'élément simple et indivisible avec le continu étendu et divisible. Ces réflexions, révolutionnaires à l'époque, restent aujourd'hui encore d'une étonnante modernité. Dans la science moderne, l'élément simple et indivisible, c'est le grain, grain (...) de matière ou grain de lumière, neutron, électron ou photon. Par contre, dans les théories nouvelles comme dans les anciennes, l'étendue continue et divisible, c'est essentiellement le champ, c'est-à-dire l'ensemble des propriétés physiques qui caractérisent à chaque instant les divers points de l'espace et qui s'expriment par des fonctions généralement continues des coordonnées d'espace et de temps. Mais les conceptions antinomiques de grain et de champ doivent nécessairement en fin de compte venir à la rencontre l'une de l'autre puisqu'elles doivent trouver leur place côte à côte dans le cadre de la Physique totale. Comment les concilier? (shrink)

The general properties of measurements in microphysics are studied and the three types of probabilities that, according to the authors, appear in wave mechanics are set up. Such a distinction, together with the principle of the localization of the corpuscle as was laid down at the very introduction of the theory of the double solution, provides a good grasp of certain phenomena whose explanation according to the usual theory (which makes no use of permanent localization and where the three types (...) of probabilities are intermingled) leads to paradoxical or self-contradictory situations. (shrink)

MATTER AND LIGHT The New Physics By LOUIS DE BROGLIE. Originally published in 1937. TRANSLATORS NOTE: THE Author has in certain places modified the original French text for the English translation, for the sake of greater cohesion, and has also revised some passages, in order to bring them into accord with the results of later research. Occasional Translators Notes are shown in square brackets. The chapter on The Undulatory Aspects of the Electron has the special historical interest of having been (...) delivered as a Lecture on the occasion of the Authors receipt of the Nobel Award, while that on Wave Mechanics and its Interpretations was given as an Address at the Glasgow meeting of the British Association in 1928. I am indebted to Dr. J. E. Turner, of the University of Liver pool, for assistance with the translation and the proofs, and to Dr. C. Strachan, of the same University, I am indebted for valuable assistance in dealing with the equations and the more technical passages, as well as for reading the proofs. W. H. J. PREFACE: THE amiable insistence of my friend Andr George has induced me to collect in the present Volume a number of Studies on con temporary Physics written from both the general and the more metaphysical point of view. Each of these Studies forms an inde pendent whole, and can be read by itself. A slight degree of repeti tion which the reader is asked to overlook has been the inevi table result for on more than one occasion I have been compelled to duplicate a summary of the great fundamental stages of con temporary Physics, such as the classification of simple substances, the investigation of the photo-electric effect and the origin of the Theory of Light Quanta and of Wave Mechanics the subjects are somewhat technical, and I cannot well assume that they are common knowledge. But though the same subject is outlined in several of these Studies, I have tried to take up a different point of view in each, and have endeavoured to throw light on different aspects of the essential problems of Quantum Physics in order to facilitate a grasp of their importance. On comparing the different chapters the reader will observe that, while overlapping, they also complement one another and he will feel the fascination and greatness inherent in the vast structure of modern Physics. And while admiring the vast number and the extreme delicacy of experimental facts which laboratory physicists have succeeded in revealing, and the strange and brilliant concepts devised by theorists to explain them, he will appreciate to what a degree the methods and ideas of physicists have grown in subtlety during recent years, and how great has been the progress from the somewhat ingenuous Realism and the over-simplified Mechanics of earlier thinkers. The more deeply we descend into the minutest structures of Matter, the more clearly we see that the concepts evolved by the mind in the course of everyday experience especially those of Time and Space must fail us in an endeavour to describe the new worlds which we are entering. One feels tempted to say that the outlines of our concepts must undergo a progressive blurring, in order that they may retain some semblance of relevance to the realities of the subatomic scales. Time and Space, in other words, are too loose a dress for the elementary entities individuality becomes attenuated in the mysterious pro cesses of interaction, and even Determinism, the darling of an older generation of physicists, is forced to yield... (shrink)

La physique moderne et l'oeuvre de Fresnel.--Ondes et corpuscules dans la physique actuelle.--La crise récente le l'optique ondulatoire.--Comme la lumière les électrons peuvent interférer.--Déterminisme et causalité dans la physique contemporaine.

Pour le physicien, le déterminisme doit être défini par la possibilité de prévoir exactement les phénomènes à venir à partir de données extraites des observations passées ou présentes. Or, dans la Physique quantique actuelle, le déterminisme ainsi défini n’existe plus pour les phénomenes individuels de l’échelle atomique. C’est ce que montrent clairement des exemples simples. Cependant en adoptant une définition un peu large du mot « causalité », il paraît permis de dire qu’en Physique quantique, s’il n’y a plus déterminisme, (...) il у а encore causalité. (shrink)