Louis Victor de Broglie , duke of Broglie, born with Dieppe the August 15th 1892 and dead the March 19th 1987 with Louveciennes, was a Mathématicien, physicist and academician French, prize winner, in 1929, Nobel Prize of physics for its “theory on the undulatory nature of the electron”.

Biography

Louis de Broglie (to pronounce breuil ) is resulting from the Maison of Broglie.

He is laid off be-letters at 18 years in 1910. He is affected during the First World War with the radio transmitter of the Eiffel Tower. He is initiated with work of modern physics by his brother Maurice de Broglie who gets to him an use of secretary of the Solveig meetings. If one refers to the biography of HTTP: /nobelprize.org/nobel_prizes/physics/laureates/1929/broglie-bio.html Nobel S, it is at 32 years, in 1924, eight years after the end of the First World War, which it supports a thesis of purely theoretical doctorate in front of a jury including/understanding Paul Langevin and Jean Perrin. This thesis will be worth four years later to him, being “nobelisable” at thirty-six years, to be named university lecturer with the Faculty of Science of the university of Paris (Institute Henri Poincaré), and a year later at 37 years, in 1929, will be worth the to him Nobel Prize of physics for its “discovery of the undulatory nature of the electron”, its theoretical thesis having been completely confirmed by two American experimenters Davisson and Germer which carried out the first electron diffraction by a crystal.

This experiment producing of the interferences of electron confirmed without ambiguity the assumption of Broglie.

Its work HTTP: /www.ensmp.fr/aflb/LDB-oeuvres/LDB-oeuvres-a.htm ref. on the undulatory nature of the electrons make of him the physicist who associated a wave with the mass particles.

In 1933, it obtains the pulpit of physical theories of the Henri-Poincaré Institute, succeeding Leon Brillouin and is elected member of the Academy of Science of which he became perpetual secretary in 1942.

Its work is important: he wrote two hundred reports and forty-five books, of which works of high popularization ( Matière and Lumière, On the paths of science, Certitudes and uncertainties of science ).

He becomes foreign member of the Royal Society in 1953.

Principal theories

Matter and dualism wave-corpuscle

See also: Duality wave-corpuscle

“The fundamental idea of thesis of 1924 was the following one: “The fact that, since the introduction by Einstein of the photons into the light wave, one knew that the light contains particles which are concentrations of energy incorporated in the wave, suggests that any particle, like the electron, must be transported by a wave in which it is built-in”… My essential idea was to extend to all the particles the coexistence of the waves and the corpuscles discovered by Einstein in 1905 in the case of the light and the photons. ” “With any material particle of mass m and speed v must be " associée" a real wave” connected to the momentum by the relation:

$\backslash \; lambda\; =\; \backslash \; frac\; \{H\}\; \{p\}\; =\; \backslash \; frac\; \{H\}\; \backslash \; sqrt\; \{1\; -\; \backslash \; frac\; \{v^2\}\; \{c^2\}\}$

where $\backslash \; lambda$ is the Wavelength, $h$ the Constante of Planck, $p$ the Quantité of movement, $m$ the Rest mass, $v$ its Speed and $c$ the Célérité of the light in the vacuum.

This theory posed the bases of the wave mechanics. It was supported by Einstein, was confirmed by the experiments of diffraction of the electrons of Davisson and Germer, and was especially generalized by work of Schrödinger.

However this generalization was statistical and was not approved by Broglie, which said “that the particle must be the seat of a periodic movement interns and that it must move in its wave in order to remain in phase with it, ignored physicists current quantists are the wrong to consider a wave propagation without localization of particle, which was completely contrary with my primitive ideas. ”

Let us note that, from the philosophical point of view, this theory of the matter waves is what the most contributed to ruin the atomism of formerly. At the origin, of Broglie thought that a real wave (i.e. having a direct physical interpretation) was associated with the particles. It proved that the undulatory aspect of the matter is formalized by a Fonction of wave controlled by the equation of Schrödinger which is a pure mathematical entity having a probabilistic interpretation, without support of real physical elements. This function of wave gives to the matter appearances of an undulatory behavior, without to utilize real physical waves. However, from Broglie returned towards the end of its life to a direct and real physical interpretation of the matter waves, following work of David Bohm. The theory of Broglie-Bohm is only interpretation today giving a real statute to the matter waves and respecting the predictions of the quantum theory. But presenting a certain number of basic problems, and not going further in its predictions than the interpretation of Copenhagen, she is recognized little by the scientific community.

Not nullity and variability of the mass

Not important, at Broglie the neutrino and the photon have both a rest mass nonnull though very low. The mass not completely null of the photon is essential by the coherence of its theory. Incidentally this rejection of the assumption of a photon of null mass enabled him to doubt the assumption of the expansion of the universe.

Also he considers that the clean mass of the particles is not constant but variable, each corpuscle which can be represented like a thermodynamic machine are equivalent to a cyclic integral of Action.

Generalization of the principle of the least action

In the second part of its thesis of 1924, of Broglie used the equivalence of the mechanical principle of the least action with the optical principle of Fermat: “The principle of Fermat applied to the wave of phase is identical to the principle of Maupertuis applied to the mobile; the possible dynamic trajectories of the mobile are identical to the possible rays of the wave”. This equivalence had been noticed by Hamilton one century, and had been before published by this one about 1830, at one time when no experiment justified to call into question the basic principles of Physics for the description of the atomic phenomena.

Until its last work, it appears to be the physicist who the most continued this dimension of Action whose max Planck, at the beginning of the XXe century, had shown that it is finally the only universal unit (with its dimension of entropy).

Duality of the natural laws

Far from to claim to make “to disappear contradiction” as max Born believed to reach that point with the statistical artifice, of Broglie has not only extended duality wave-corpuscle to all corpuscles (and even with the crystals which reveals effects of diffraction), but also wide the principle of duality to the natural laws.

Its last work makes Thermodynamics and Mechanics two great systems of laws, with the work at the same time, and which it joins together in only one system: “When the Boltzmann and its continuators developed their statistical interpretation of Thermodynamics, one could consider Thermodynamics as a complicated branch of Dynamics. But, with my current ideas, it is the Dynamics which appears as a simplified branch of Thermodynamics. I think that, of all the ideas that I introduced in quantum theory into these last years, it is this idea which is, of much, most important and deepest. ”

This design appears to correspond to the duality continuous-discontinuous, its Dynamics being able to be the limit of its Thermodynamics when sequences in extreme cases continuous are postulated. It is also close to that of Leibniz, which posed the need for " principles architectoniques" to supplement the system of the mechanical laws.

However there is at his place less duality, within the meaning of opposition, that synthesis (one is the limit of the other) and the effort of synthesis is constant at his place, already in its very first formula, where the first member belongs to mechanics and the second to optics:

$m\; c^2\; =\; H\; \backslash \; naked$

Theory neutrinienne of the light

This theory, which goes back to 1934, introduces the idea that the photon would be equivalent to the fusion of two neutrinos of Dirac.

It shows that the movement of the center of gravity of these two particles obeys the Maxwell's equations - what implies that the neutrino and the photon have both a rest mass nonnull though very low.

Hidden thermodynamics

The last great idea of Broglie is the hidden Thermodynamics of the isolated particle. It is an attempt to join together the three extrêmaux great principles of physics: principles of Fermat, Maupertuis and Carnot.

In this ultimate work, the Action becomes a kind of opposite of the entropy, by an equation which connects of two only universal dimensions, of the form:

$\{Action\; \backslash \; over\; H\}\; =\; -\; \{Entropy\; \backslash \; over\; K\}$

Consequence of great range, this theory brings back the quantum indetermination to variations around the extrema of the Action, variations corresponding to reductions in the entropy .

French Academy

He was elected with the French Academy, the October 12th 1944, with the armchair 1, succeeding Emile Picard (death the December 11th 1941, and to which the academicians did not give a successor as long as the occupation of the France by the Germans lasted). Its official reception took place the May 31st 1945, giving the opportunity of a new scene since three centuries: the reception of an academician by his own brother (the duke Maurice de Broglie). After its disappearance, it was replaced, the March 24th 1988, by Michel Debré.

Decorations

• Raised, in 1961, with the dignity of Grand Cross of the Legion of honor
• Commander of the academic Palms

See too

• Foundation Louis de Broglie
• Jean-Louis Destouches

External bonds

• Card of the French Academy

• Works of Louis de Broglie

Simple: Louis de Broglie

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