Paul Langevin (; ; 23 January 1872 – 19 December 1946) was a French

physicist A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists generally are interested in the root or ultimate cau ...

who developed Langevin dynamics and the Langevin equation. He was one of the founders of the ''

Comité de vigilance des intellectuels antifascistes The Watchfulness Committee of Antifascist Intellectuals (''Comité de vigilance des intellectuels antifascistes'', CVIA) was a French political organization created in March 1934, in the wake of the February 6, 1934 riots organized by far right leag ...

'', an anti-fascist organization created after the 6 February 1934 far right riots. Being a public opponent of fascism in the 1930s resulted in his arrest and being held under house arrest by the

Vichy government Vichy France (french: Régime de Vichy; 10 July 1940 – 9 August 1944), officially the French State ('), was the fascist French state headed by Marshal Philippe Pétain during World War II. Officially independent, but with half of its terr ...

for most of

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...

. Langevin was also president of the Human Rights League (LDH) from 1944 to 1946, having recently joined the French Communist Party. He was a doctoral student of Pierre Curie and later a lover of widowed Marie Curie. He is also known for his two US patents with Constantin Chilowsky in 1916 and 1917 involving

ultrasonic Ultrasound is sound waves with frequencies higher than the upper audible limit of human hearing. Ultrasound is not different from "normal" (audible) sound in its physical properties, except that humans cannot hear it. This limit varies fr ...

submarine detection. He is entombed at the

Panthéon The Panthéon (, from the Classical Greek word , , ' empleto all the gods') is a monument in the 5th arrondissement of Paris, France. It stands in the Latin Quarter, atop the , in the centre of the , which was named after it. The edifice was b ...

Life

Langevin was born in

Paris Paris () is the Capital city, capital and List of communes in France with over 20,000 inhabitants, most populous city of France, with an estimated population of 2,165,423 residents in 2019 in an area of more than 105 km² (41 sq mi), ma ...

, and studied at the '' École de Physique et Chimie'' and the '' École Normale Supérieure''. He then went to the

University of Cambridge The University of Cambridge is a public collegiate research university in Cambridge, England. Founded in 1209 and granted a royal charter by Henry III in 1231, Cambridge is the world's third oldest surviving university and one of its most pr ...

and studied in the Cavendish Laboratory under Sir J. J. Thomson. Langevin returned to the

Sorbonne Sorbonne may refer to: * Sorbonne (building), historic building in Paris, which housed the University of Paris and is now shared among multiple universities. *the University of Paris (c. 1150 – 1970) *one of its components or linked institution, ...

and obtained his PhD from Pierre Curie in 1902. In 1904, he became Professor of Physics at the ''

Collège de France The Collège de France (), formerly known as the ''Collège Royal'' or as the ''Collège impérial'' founded in 1530 by François I, is a higher education and research establishment ('' grand établissement'') in France. It is located in Paris n ...

''. In 1926, he became director of the ''École de Physique et Chimie'' (later became ''École supérieure de physique et de chimie industrielles de la Ville de Paris'', '' ESPCI ParisTech''), where he had been educated. He was elected in 1934 to the Académie des sciences. Langevin is noted for his work on paramagnetism and

diamagnetism Diamagnetic materials are repelled by a magnetic field; an applied magnetic field creates an induced magnetic field in them in the opposite direction, causing a repulsive force. In contrast, paramagnetic and ferromagnetic materials are attracte ...

, and devised the modern interpretation of this phenomenon in terms of spins of electrons within atoms. His most famous work was in the use of ultrasound using Pierre Curie's

piezoelectric effect Piezoelectricity (, ) is the electric charge that accumulates in certain solid materials—such as crystals, certain ceramics, and biological matter such as bone, DNA, and various proteins—in response to applied mechanical stress. The word '' ...

. During

World War I World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fightin ...

, he began working on the use of these sounds to detect submarines through echo location. However the war was over by the time it was operational. During his career, Paul Langevin also spread the theory of relativity in academic circles in France and created what is now called the twin paradox. In 1898, he married Emma Jeanne Desfosses, and together they had four children, Jean, André, Madeleine and Hélène. In 1910, he reportedly had an affair with the then-widowed Marie Curie; some decades later, their respective grandchildren, grandson Michel Langevin and granddaughter Hélène Langevin-Joliot married one another. He was also noted for being an outspoken opponent of Nazism, and was removed from his post by the

following the occupation of the country by

Nazi Germany Nazi Germany (lit. "National Socialist State"), ' (lit. "Nazi State") for short; also ' (lit. "National Socialist Germany") (officially known as the German Reich from 1933 until 1943, and the Greater German Reich from 1943 to 1945) was ...

. He was later restored to his position in 1944. He died in Paris in 1946, two years after living to see the Liberation of Paris. He is buried near several other prominent French scientists in the

in Paris. In 1933, he had a son with physicist Eliane Montel (1898-1993), Paul-Gilbert Langevin, who became a renowned musicologist. His daughter, Hélène Solomon-Langevin, was arrested for Resistance activity and survived several

concentration camps Internment is the imprisonment of people, commonly in large groups, without charges or intent to file charges. The term is especially used for the confinement "of enemy citizens in wartime or of terrorism suspects". Thus, while it can simply ...

. She was on the same convoy of female political prisoners as Marie-Claude Vaillant-Couturier and

Charlotte Delbo Charlotte Delbo (10 August 1913 – 1 March 1985) was a French writer chiefly known for her haunting memoirs of her time as a prisoner in Auschwitz, where she was sent for her activities as a member of the French resistance. Biography Early life ...

Submarine detection

In 1916 and 1917, Paul Langevin and Chilowsky filed two US patents disclosing the first ultrasonic submarine detector using an electrostatic method (singing condenser) for one patent and thin quartz crystals for the other. The amount of time taken by the signal to travel to the enemy submarine and echo back to the ship on which the device was mounted was used to calculate the distance under water. In 1916, Lord Ernest Rutherford, working in the UK with his former McGill University PhD student Robert William Boyle, revealed that they were developing a

quartz Quartz is a hard, crystalline mineral composed of silica ( silicon dioxide). The atoms are linked in a continuous framework of SiO4 silicon-oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall chemical ...

piezoelectric Piezoelectricity (, ) is the electric charge that accumulates in certain solid materials—such as crystals, certain ceramics, and biological matter such as bone, DNA, and various proteins—in response to applied mechanical stress. The word '' ...

detector for submarine detection. Langevin's successful application of the use of piezoelectricity in the generation and detection of ultrasound waves was followed by further development.

References

Sources

*''Asimov's Biographical Encyclopedia of Science and Technology'', Isaac Asimov, Doubleday & Co., Inc., 1972, . * References to the affair with Marie Curie is found in Françoise Giroud (Davis, Lydia trans.), Marie Curie: A life, Holmes and Meier, 1986, , and in Quinn Susan, Marie Curie: A Life, Heinemann, 1995, .
Wolfram research biographical entry
by Michel Barran.
Annotated bibliography for Niels Bohr from the Alsos Digital Library for Nuclear Issues

External links

* * {{DEFAULTSORT:Langevin, Paul 1872 births 1946 deaths École Normale Supérieure alumni Members of the French Academy of Sciences University of Paris alumni Collège de France faculty French activists French Communist Party members French physicists Burials at the Panthéon, Paris Recipients of the Copley Medal ESPCI Paris alumni ESPCI Paris faculty Alumni of the University of Cambridge Foreign Members of the Royal Society Corresponding Members of the Russian Academy of Sciences (1917–1925) Corresponding Members of the USSR Academy of Sciences Honorary Members of the USSR Academy of Sciences Langevin family

Life

Submarine detection

See also

References

Sources

Further reading

External links