Louis de Broglie

Family and education

Louis Victor Pierre Raymond was born on 15 August 1892 in Dieppe, France, into the aristocratic House of Broglie, a noble family of Italian origin, whose representatives for several centuries occupied important military and political posts in France. His father, Louis-Alphonse-Victor, 5th duc de Broglie, was married to Pauline d'Armaille, the granddaughter of the Napoleonic General Philippe Paul, comte de Ségur, and his wife, the biographer Marie Célestine Amélie d'Armaillé. They had five children; in addition to Louis, these were: Albertina (1872–1946), subsequently the Marquise de Luppé; Maurice (1875–1960), subsequently a famous experimental physicist; Philip (1881–1890), who died two years before the birth of Louis, and Pauline, Comtesse de Pange (1888–1972), subsequently a famous writer. Per The New York Times, "a great-grandfather fought on George Washington's side in the American Revolutionary War as the chief lieutenant of the Marquis de Lafayette."

De Broglie was said to have been a good looking and charming child with an aptitude for history. Though sometimes lonely, he had a strong memory and interest in politics. He attended Lycée Janson-de-Sailly, and passed the baccalauréat in 1909. At university, he first studied literature, and received a licence ès lettres in History in 1910. Afterwards, he turned his attention towards science, receiving a licence ès sciences in 1913. With the outbreak of the First World War in 1914, he offered his services to the Wireless section of the army in the development of radio communications.

Scientific and pedagogical career

His 1924 thesis Recherches sur la théorie des quanta (Research on the Theory of the Quanta) introduced his theory of electron waves. This included the wave–particle duality theory of matter, based on the work of Max Planck and Albert Einstein on light. This research culminated in the de Broglie hypothesis stating that any moving particle or object had an associated wave. De Broglie thus created a new field in physics, the mécanique ondulatoire, or wave mechanics, uniting the physics of energy (wave) and matter (particle). He won the Nobel Prize in Physics in 1929 "for his discovery of the wave nature of electrons".

In his later career, de Broglie worked to develop a causal explanation of wave mechanics, in opposition to the wholly probabilistic models which dominate quantum mechanical theory; it was refined by David Bohm in the 1950s. The theory has since been known as the De Broglie–Bohm theory.

In addition to strictly scientific work, de Broglie thought and wrote about the philosophy of science, including the value of modern scientific discoveries. In 1930 he founded the book series Actualités scientifiques et industrielles published by Éditions Hermann.

De Broglie became a member of the Académie des sciences in 1933, and was the academy's perpetual secretary from 1942. He was asked to join Le Conseil de l'Union Catholique des Scientifiques Francais, but declined because he was non-religious.

In 1941, he was made a member of the National Council of Vichy France. On 12 October 1944, he was elected to the Académie Française, replacing mathematician Émile Picard. Because of the deaths and imprisonments of Académie members during the occupation and other effects of the war, the Académie was unable to meet the quorum of twenty members for his election; due to the exceptional circumstances, however, his unanimous election by the seventeen members present was accepted. In an event unique in the history of the Académie, he was received as a member by his own brother Maurice, who had been elected in 1934. UNESCO awarded him the first Kalinga Prize in 1952 for his work in popularizing scientific knowledge, and he was elected a Foreign Member of the Royal Society on 23 April 1953.

Louis became the 7th duc de Broglie in 1960 upon the death without heir of his elder brother, Maurice, 6th duc de Broglie, also a physicist.

In 1961, de Broglie received the title of Knight of the Grand Cross in the Legion of Honour. De Broglie was awarded a post as counselor to the French High Commission of Atomic Energy in 1945 for his efforts to bring industry and science closer together. He established a center for applied mechanics at the Henri Poincaré Institute, where research into optics, cybernetics, and atomic energy were carried out. He inspired the formation of the International Academy of Quantum Molecular Science and was an early member.

De Broglie never married. When he died on 19 March 1987 in Louveciennes at the age of 94, he was succeeded as duke by a distant cousin, Victor-François, 8th duc de Broglie. His funeral was held 23 March 1987 at the Church of Saint-Pierre-de-Neuilly. Jean-Claude Lehmann, director of the physics department at France's National Center for Scientific Research, said: "The death of Louis de Broglie marks the disappearance of one of the most brilliant pioneers in contemporary physics."