Editing Pyotr Kapitsa (section)

== Biography ==
Kapitsa was born in [[Kronstadt]], [[Russian Empire]], to the [[Bessarabia]]n Leonid Petrovich Kapitsa ({{langx|ro|Leonid Petrovici Capița}}), a [[military engineering-technical university|military engineer]] who constructed fortifications, and to the [[Volhynia]]n Olga Ieronimovna Kapitsa, from a [[szlachta|noble Polish]] Stebnicki family.<ref>''[[Tadeusz Gajl]] (2007)''. [http://gajl.wielcy.pl/herby_lista.php?query=9Stebnicki&startp=0&herbcnt=2&lang=en Polish Armorial Middle Ages to 20th Century]. — Gdańsk: L&L {{ISBN|978-83-60597-10-1}}</ref><ref>[https://ru.wikisource.org/wiki/%D0%AD%D0%A1%D0%91%D0%95/%D0%A1%D1%82%D0%B5%D0%B1%D0%BD%D0%B8%D1%86%D0%BA%D0%B8%D0%B5 Stebnytski noble family] from [[Brockhaus and Efron Encyclopedic Dictionary]] at [[Wikisource]], 1890–1907 (in Russian)</ref> Besides [[Russian language|Russian]], the Kapitsa family also spoke [[Romanian language|Romanian]].<ref name=Sergey>{{cite web|url=http://mdn.md/index.php?day=3498 |title=Ilustrul savant rus de origine basarabeană, academicianul Serghei Petrovici Capița, împlinește azi 80 de ani|language=ro|access-date=2009-04-21 |publisher=MDN News Magazine|archive-url=https://web.archive.org/web/20131029191828/http://mdn.md/index.php?day=3498|archive-date=2013-10-29 }}</ref>
[[File:Yoffe_Seminar_1915.jpg|thumb|left|Kapitsa, standing leftmost with Professor [[Abram Ioffe]] (seated fourth from left) in 1915]]
Kapitsa's studies were interrupted by the [[First World War]], in which he served as an ambulance driver for two years on the [[Eastern Front (World War I)|Polish front]].<ref name="James2004">{{cite book |last=James |first=Ioan |author-link=Ioan James |title=Remarkable Physicists: From Galileo to Yukawa |url=https://archive.org/details/remarkablephysic00jame |url-access=limited |year=2004 |publisher=Cambridge University Press |isbn=978-0-521-01706-0 |pages=[https://archive.org/details/remarkablephysic00jame/page/n336 320]–327}}</ref> He graduated from the [[Petrograd Polytechnical Institute]] in 1918. His wife and two children died in the flu epidemic of 1918–19. He subsequently studied in [[United Kingdom|Britain]], working for over ten years with [[Ernest Rutherford]] in the [[Cavendish Laboratory]] at the [[University of Cambridge]], and founding the influential [[Kapitza club]]. He was the first director (1930–34) of the [[New Museums Site|Mond Laboratory]] in Cambridge.<ref>{{cite web |url=https://cudl.lib.cam.ac.uk/view/PH-CAVENDISH-P-00414/1 |website=University of Cambridge Digital Library |publisher=University of Cambridge |access-date=12 October 2022|title=Cavendish Laboratory : Portrait of Pyotr Kapitza }}</ref>

In the 1920s he originated techniques for creating ultrastrong [[magnetic field]]s by injecting high [[electrical current|current]] for brief periods into specially constructed air-core [[electromagnet]]s. In 1928 he discovered the linear relation between resistivity and magnetic field strength in various metals under very strong magnetic fields.<ref name=nobel />

In 1934 Kapitsa returned to Russia to visit his parents but the Soviet Union prevented him from travelling back to Great Britain.<ref>{{cite journal |title=Prof. P. Kapitza and the U.S.S.R |journal=Nature |date=1 May 1935 |volume=135 |issue=3418 |pages=755–756 |doi=10.1038/135755a0 |bibcode=1935Natur.135..755. |s2cid=4113390 |doi-access=free }}</ref>

As his equipment for high-magnetic field research remained in Cambridge (although later Ernest Rutherford negotiated with the British government the possibility of shipping it to the USSR), he changed the direction of his research to the study of low temperature phenomena, beginning with a critical analysis of the existing methods for achieving low temperatures. In 1934 he developed new and original apparatus (based on the [[adiabatic principle]]) for making significant quantities of [[liquid helium]].{{fact|date=April 2022}}

Kapitsa participated in formation of the [[Institute for Physical Problems]], in part using equipment which the Soviet government bought from the Mond Laboratory in Cambridge (with the assistance of Rutherford, once it was clear that Kapitsa would not be permitted to return).{{fact|date=April 2022}}

In Russia, Kapitsa began a series of experiments to study [[liquid helium]]. This research culminated with the 1937 discovery of [[superfluidity]] (another expression of the [[Bose–Einstein condensate|state of matter]] that gives rise to [[superconductivity]]). Beginning with a letter to the editor of ''Science'' on 8 January 1938 where he reported the absence of measurable viscosity in liquid helium-4 cooled below 1.8 K, Kapitza documented the properties of helium-4 superfluid in a series of papers. This was the body of work for which he was later awarded the Nobel Prize in Physics, "basic inventions and discoveries in the area of low-temperature physics".<ref>{{Cite web |title=The Nobel Prize in Physics 1978 |url=https://www.nobelprize.org/prizes/physics/1978/kapitsa/facts/ |access-date=2023-04-11 |website=NobelPrize.org |language=en-US}}</ref>

In 1939 he developed a new method for liquefaction of air with a low-pressure cycle using a special high-efficiency expansion turbine. Consequently, during World War II he was assigned to head the Department of Oxygen Industry attached to the [[USSR Council of Ministers]], where he developed his low-pressure expansion techniques for industrial purposes. He invented high power microwave generators (1950–1955) and discovered a new kind of continuous high pressure plasma discharge with electron temperatures over 1,000,000 K.{{fact|date=April 2022}}

In November 1945 Kapitsa quarreled with [[Lavrentiy Beria]], head of the [[NKVD]] and in charge of the [[Soviet atomic bomb project]], writing to [[Joseph Stalin]] about Beria's ignorance of physics and his arrogance. Stalin backed Kapitsa, telling Beria he had to cooperate with the scientists. Kapitsa refused to meet Beria: "If you want to speak to me, then come to the Institute." Stalin offered to meet Kapitsa, but this never happened.<ref>[[Simon Sebag Montefiore|Montefiore, Simon Sebag]] (2008) ''Young Stalin'', pp. 446–7. {{ISBN|1400096138}}.</ref>

Immediately after the war, a group of prominent Soviet scientists (including Kapitsa in particular) lobbied the government to create a new technical university, the [[Moscow Institute of Physics and Technology]]. Kapitsa taught there for many years. From 1957, he was also a member of the presidium of the [[Academy of Sciences of the Soviet Union|Soviet Academy of Sciences]] and at his death in 1984 was the only presidium member who was not also a member of the [[Communist Party of the Soviet Union|Communist Party]].<ref>[[Loren Graham|Graham, Loren R.]] 1994. ''Science in Russia and the Soviet Union: A Short History''. Cambridge University Press. p. 212. {{ISBN|0-521-28789-8}}.</ref>

In 1966 Kapitsa was allowed to visit Cambridge to receive the [[Rutherford Medal and Prize]].<ref>{{cite news | last = Tucker | first = Anthony | title = Dr Peter Kapitza expected in Britain next month | newspaper = [[The Guardian]] | pages = 4 | date = 1966-04-04 | url = https://www.newspapers.com/image/259503770/ | access-date = 2019-03-16}}{{subscription required|via=newspapers.com}}</ref> While dining at his old college, [[Trinity College, Cambridge|Trinity]], he found he did not have the required [[Academic dress in the United Kingdom#Gown|gown]]. He asked to borrow one, but a college servant asked him when he last dined at [[high table]], "Thirty-two years" replied Kapitza. Within moments the servant returned, not with any gown, but Kapitsa's own.<ref>{{cite news | title = Carry on Jeeveski | newspaper = [[The Guardian]] | pages = 10 | date = 1966-05-05 | url = https://www.newspapers.com/image/259513982/ | access-date = 2019-03-16}}{{subscription required|via=newspapers.com}}</ref>

[[File:KustodiyevSemenov Kapitsa.JPG|thumb|Kapitsa (left) and [[Nikolay Semyonov]], the physics and chemistry Nobel laureates (portrait by [[Boris Kustodiev]], 1921).]]
In 1978 Kapitsa won the [[Nobel Prize in Physics]] "for his basic inventions and discoveries in the area of [[Cryogenics|low-temperature physics]]" and was also cited for his long term role as a leader in the development of this area. He shared the prize with [[Arno Allan Penzias]] and [[Robert Woodrow Wilson]], who won for discovering the [[cosmic microwave background]].<ref>{{cite web |title=The Nobel Prize in Physics 1978 – Press Release |url=https://www.nobelprize.org/nobel_prizes/physics/laureates/1978/press.html |publisher=Nobel Prize.org |date=17 October 1978}}</ref>

''[[Interfacial thermal resistance|Kapitsa resistance]]'' is the thermal resistance (which causes a temperature discontinuity) at the interface between [[liquid helium]] and a solid. The ''[[Kapitsa–Dirac effect]]'' is a [[quantum mechanics|quantum mechanical]] effect consisting of the diffraction of electrons by a [[standing wave]] of light. In [[fluid dynamics]], the ''[[Kapitza number]]'' is a dimensionless number characterizing the flow of thin films of fluid down an incline.