Louis de Broglie


Prince Louis Victor Pierre Raymond de Broglie belonged to an ancient and famous family. From the seventeenth century on, this family produced several religious leaders, two Marshals of France and two prime ministers. However, both Louis and his older brother Maurice broke from family tradition by taking an active interest in science. While his older brother played a role in this shift of interest, de Broglie also stated that the works of French mathematician Henri Poincare were decisive in changing his mind. The same year de Broglie completed a science degree from the University of Paris, he was drafted into military service. During World War I, de Broglie was stationed in Paris in the Eiffel Tower, working as a wireless operator.

After the war, in 1918, de Broglie joined his brother on X-ray research. Their work dealt with the spectrum of electrons released by X rays at given frequencies and was directly related to the new model of the atom developed by Niels Bohr. By 1924, the brothers became intrigued by a discovery of Arthur Compton. When a quantum of light, which Compton called a "photon", struck an electron, the photon would lose some of its energy and would become a light wave of longer wavelength. Thus, the light photon acted more like a particle than a wave. All the components for a new view of the physical world were now available, and de Broglie proposed the wave-particle duality: Not only could waves act like particles, but particles could also act like waves. De Broglie presented the idea that an electron in orbit around a nucleus represented a specific wavelength. When energy was applied to the atom, the electron would jump to a higher orbit that was equal to an integral number of the electron wavelength. When an electron returned to a lower orbit, the excess energy would be given off as one photon of light.

In 1924, de Broglie presented this analysis as his doctoral dissertation, entitled "Research on the Quantum Theory" to the University of Paris. He suggested on theoretical grounds that any particles, not only photons, traveling with a momentum p should have (in some sense) a wavelength given by the de Broglie relation:

.lambda. = h/p

The faculty viewed his idea with skepticism, since there existed no experimental evidence to support his view. With the support and encouragement of Albert Einstein, however, de Broglie was awarded his degree and went on to publish his work. Einstein began to promote this analysis among other physicists. Schrodinger used this idea of the dual nature of matter to develop a theory of wave mechanics. By 1927, Davisson and Thomson, working independently were able to demonstrate that electrons could be bent, focused, and diffracted like waves. As a result of this experimental confirmation and for his contribution to quantum mechanics, de Broglie was awarded the Nobel Prize in Physics in 1929. He continued to spend the rest of his life devoted to the study of science.


Chen, Victor W., The Great Scientists, p. 6-10, Grolier Educational Corporation, Danbury, Conneticut.


Source: Joseph Mezzapelle 1998


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