Paul Langevin

Paul Langevin ( born January 23, 1872 in Paris, † December 19, 1946 ) was a French physicist.

Paul Langevin studied at the École supérieure de physique et de chimie de la ville de Paris industrial and sat there and continued his career, most recently as director of this university. Since 1909 he held a professorship in physics at the Collège de France.

Langevin worked on the moderation of neutrons, thus laying a foundation for the construction of nuclear reactors.

The Langevin equation stochastic differential equation is used in statistical physics to describe processes in the presence of random microscopic force (noise), for example, the Brownian movement of gas molecules. He is named after the Langevin function.

He spent the first 1916, the piezoelectricity of quartz crystals with the construction of the first ultrasonic object detection (sonar ) technology and developed for the French Navy, the first sonar system. The discovery of the piezoelectric effect, however, goes to the Curie brothers in 1880 (see Reset the piezoelectric effect ).

Mitbenannt After Langevin is the Institute Laue-Langevin in Grenoble and the Institut Langevin - Ondes et Images in Paris.

Private life

His personal connection with the Nobel Prize winner Marie Curie became known as " Langevin affair" in 1910 to the public.

Langevin was a pacifist. He was a demonstration German pacifists under the motto Never again war! Invited in Berlin in 1923, also took part, but refused to take the floor; the question of war guilt quarreled nor the two peoples.

In 1934 he founded, together with the philosopher Alain a committee of vigilance (opposite martial aspirations ), where many prominent intellectuals presented from different ideological camps available.