French physicist. In 1928 he became professor in the faculty of sciences, Univ. of Paris. It was known from the earlier quantum theory that light waves sometimes exhibited a particlelike behavior. De Broglie hypothesized (1924) that particles should also exhibit certain wavelike properties, a prediction that led to the development of wave mechanics, a form of quantum mechanics. The existence of these matter waves was confirmed experimentally in 1927, and de Broglie received the 1929 Nobel Prize in Physics for his theory. He was elected permanent secretary of the Academy of Sciences in 1942. In recognition of his talents as a writer, he was elected to the French Academy in 1944. His many works on physics and the philosophy of science include An Introduction to the Study of Wave Mechanics (1930, tr. 1930), Revolution in Physics (tr. 1953), and Non-Linear Wave Mechanics (1956, tr. 1960).