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 In physics, a Langevin equation (named after Paul Langevin) is a stochastic differential equation describing how a system evolves when subjected to a combination of deterministic and fluctuating ("random") forces. The dependent variables in a Lange ...

. He was one of the founders of the '' Comité de vigilance des intellectuels antifascistes'', 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 (; 10 July 1940 – 9 August 1944), officially the French State ('), was a French rump state headed by Marshal Philippe Pétain during World War II, established as a result of the French capitulation after the defeat against ...

for most of

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

. Langevin was also president of the Human Rights League (LDH) from 1944 to 1946, having recently joined the

French Communist Party The French Communist Party (, , PCF) is a Communism, communist list of political parties in France, party in France. The PCF is a member of the Party of the European Left, and its Member of the European Parliament, MEPs sit with The Left in the ...

. He was a doctoral student of

Pierre Curie Pierre Curie ( ; ; 15 May 1859 – 19 April 1906) was a French physicist, Radiochemistry, radiochemist, and a pioneer in crystallography, magnetism, piezoelectricity, and radioactivity. He shared the 1903 Nobel Prize in Physics with his wife, ...

and later a lover of widowed

Marie Curie Maria Salomea Skłodowska-Curie (; ; 7 November 1867 – 4 July 1934), known simply as Marie Curie ( ; ), was a Polish and naturalised-French physicist and chemist who conducted pioneering research on radioactivity. She was List of female ...

. He is also known for his two US patents with Constantin Chilowsky in 1916 and 1917 involving ultrasonic

submarine A submarine (often shortened to sub) is a watercraft capable of independent operation underwater. (It differs from a submersible, which has more limited underwater capability.) The term "submarine" is also sometimes used historically or infor ...

detection. He is entombed at the

Panthéon The Panthéon (, ), is a monument in the 5th arrondissement of Paris, France. It stands in the Latin Quarter, Paris, Latin Quarter (Quartier latin), atop the , in the centre of the , which was named after it. The edifice was built between 1758 ...

Life

Langevin was born in

Paris Paris () is the Capital city, capital and List of communes in France with over 20,000 inhabitants, largest city of France. With an estimated population of 2,048,472 residents in January 2025 in an area of more than , Paris is the List of ci ...

, and studied at the '' École de Physique et Chimie'' and the ''

École Normale Supérieure École or Ecole may refer to: * an elementary school in the French educational stages normally followed by Secondary education in France, secondary education establishments (collège and lycée) * École (river), a tributary of the Seine flowing i ...

''. He then went to the

University of Cambridge The University of Cambridge is a Public university, public collegiate university, collegiate research university in Cambridge, England. Founded in 1209, the University of Cambridge is the List of oldest universities in continuous operation, wo ...

and studied in the

Cavendish Laboratory The Cavendish Laboratory is the Department of Physics at the University of Cambridge, and is part of the School of Physical Sciences. The laboratory was opened in 1874 on the New Museums Site as a laboratory for experimental physics and is named ...

under Sir J. J. Thomson. Langevin returned to the Sorbonne and obtained his

PhD A Doctor of Philosophy (PhD, DPhil; or ) is a terminal degree that usually denotes the highest level of academic achievement in a given discipline and is awarded following a course of graduate study and original research. The name of the deg ...

from

in 1902. In 1904, he became

Professor Professor (commonly abbreviated as Prof.) is an Academy, academic rank at university, universities and other tertiary education, post-secondary education and research institutions in most countries. Literally, ''professor'' derives from Latin ...

of Physics at the ''

Collège de France The (), formerly known as the or as the ''Collège impérial'' founded in 1530 by François I, is a higher education and research establishment () in France. It is located in Paris near La Sorbonne. The has been considered to be France's most ...

''. 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 The French Academy of Sciences (, ) is a learned society, founded in 1666 by Louis XIV at the suggestion of Jean-Baptiste Colbert, to encourage and protect the spirit of French Scientific method, scientific research. It was at the forefron ...

. Langevin is noted for his work on

paramagnetism Paramagnetism is a form of magnetism whereby some materials are weakly attracted by an externally applied magnetic field, and form internal, induced magnetic fields in the direction of the applied magnetic field. In contrast with this behavior, ...

and

diamagnetism Diamagnetism is the property of materials that 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 ferromagnet ...

, and devised the modern interpretation of this phenomenon in terms of

electron The electron (, or in nuclear reactions) is a subatomic particle with a negative one elementary charge, elementary electric charge. It is a fundamental particle that comprises the ordinary matter that makes up the universe, along with up qua ...

spin. His most famous work was in the use of

ultrasound Ultrasound is sound with frequency, frequencies greater than 20 Hertz, kilohertz. This frequency is the approximate upper audible hearing range, limit of human hearing in healthy young adults. The physical principles of acoustic waves apply ...

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 stress (mechanics), mechanical s ...

. During

World War I World War I or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a World war, global conflict between two coalitions: the Allies of World War I, Allies (or Entente) and the Central Powers. Fighting to ...

, he began working on the use of these sounds to detect

s through echo location, though the war ended before the system became operational. During his career, Paul Langevin also spread the

theory of relativity The theory of relativity usually encompasses two interrelated physics theories by Albert Einstein: special relativity and general relativity, proposed and published in 1905 and 1915, respectively. Special relativity applies to all physical ph ...

in academic circles in France and created what is now called the

twin paradox In physics, the twin paradox is a thought experiment in special relativity involving twins, one of whom takes a space voyage at relativistic speeds and returns home to find that the twin who remained on Earth has aged more. This result appear ...

. 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

; some decades later, their respective grandchildren, grandson and granddaughter Hélène Langevin-Joliot married one another. He was also noted for being an outspoken opponent of

Nazism Nazism (), formally named National Socialism (NS; , ), is the far-right totalitarian socio-political ideology and practices associated with Adolf Hitler and the Nazi Party (NSDAP) in Germany. During Hitler's rise to power, it was fre ...

, and was removed from his post by the

following the occupation of the country by

Nazi Germany Nazi Germany, officially known as the German Reich and later the Greater German Reich, was the German Reich, German state between 1933 and 1945, when Adolf Hitler and the Nazi Party controlled the country, transforming it into a Totalit ...

. 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 The liberation of Paris () was a battle that took place during World War II from 19 August 1944 until the German garrison surrendered the French capital on 25 August 1944. Paris had been occupied by Nazi Germany since the signing of the Armisti ...

. 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 Paul-Gilbert Langevin (Boulogne-Billancourt, 5 July 1933 – Paris, 4 July 1986) was a French musicologist, who was a specialist on Anton Bruckner, Franz Schubert and 19th-century classical music. History Paul-Gilbert Langevin was the son of Fre ...

, who became a renowned musicologist. His daughter, Hélène Solomon-Langevin, was arrested for Resistance activity and survived several

concentration camps A concentration camp is a prison or other facility used for the internment of political prisoners or politically targeted demographics, such as members of national or ethnic minority groups, on the grounds of national security, or for exploit ...

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

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 Ernest Rutherford, 1st Baron Rutherford of Nelson (30 August 1871 – 19 October 1937) was a New Zealand physicist who was a pioneering researcher in both atomic and nuclear physics. He has been described as "the father of nuclear physics", ...

, working in the UK with his former

McGill University McGill University (French: Université McGill) is an English-language public research university in Montreal, Quebec, Canada. Founded in 1821 by royal charter,Frost, Stanley Brice. ''McGill University, Vol. I. For the Advancement of Learning, ...

PhD student Robert William Boyle, revealed that they were developing a

quartz Quartz is a hard, crystalline mineral composed of silica (silicon dioxide). The Atom, atoms are linked in a continuous framework of SiO4 silicon–oxygen Tetrahedral molecular geometry, tetrahedra, with each oxygen being shared between two tet ...

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 stress (mechanics), mechanical s ...

detector for

detection. Langevin's successful application of the use of

piezoelectricity 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 piezoel ...

in the generation and detection of

waves was followed by further development.

References

Sources

*''Asimov's Biographical Encyclopedia of Science and Technology'',

Isaac Asimov Isaac Asimov ( ; – April 6, 1992) was an Russian-born American writer and professor of biochemistry at Boston University. During his lifetime, Asimov was considered one of the "Big Three" science fiction writers, along with Robert A. H ...

, 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 Academic staff of the Collège de France French activists French Communist Party members French physicists Burials at the Panthéon, Paris Recipients of the Copley Medal ESPCI Paris alumni Academic staff of ESPCI Paris 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 Honorary commanders of the Order of the British Empire Grand Cross of the Legion of Honour

Life

Submarine detection

See also

References

Sources

Further reading

External links