Louis de Broglie, 94; Won 1929 Nobel Prize in Physics

Louis de Broglie, whose pioneering efforts in theoretical physics brought him the 1929 Nobel Prize, died Thursday at a Paris hospital, the French Academy announced.

De Broglie, 94, helped reconcile what were seen as contradictions between the wave theory and the particle theory of radiation, offering the hypothesis that particles could exhibit certain wavelike properties.

In 1927, experiments proved his theory correct, leading to the development of wave mechanics, a form of quantum mechanics.

“The death of Louis de Broglie marks the disappearance of one of the most brilliant pioneers in contemporary physics,” said Jean-Claude Lehmann, director of the physics department at France’s National Center for Scientific Research.

De Broglie was born into a prominent aristocratic family. His father was Victor de Broglie, a member of the French Parliament. Others in the family were prominent military and political figures and scientists. His grandfather, Albert, was a prime minister of France in the 1870s.

De Broglie, who switched to physics after completing a traditional French literary education, was introduced to science by his brother, Maurice, 17 years his senior, who had set up a home laboratory for X-ray research. Together they wrote “Introduction to the Study of X and Gamma Rays,” published in 1928.

When Maurice died in 1960, his title of duke passed to his younger brother.

Louis de Broglie was secretary of the French Academy of Science from 1942 to 1975, a member of the French Legion of Honor, the French Academy and the recipient of many prizes during his long career.

He also was known for scientific works with popular appeal, including “The Certitudes and Incertitudes of Science” (1966), “A Half-Century’s Research” (1979) and “Landmarks for New Microphysics” (1978).