Kagan, Yuri Moiseevich

Born July 6, 1928 in Moscow in a family of natives of Vitebsk . His father, Moses Aleksandrovich Kagan (1889-1966), the son of a merchant of the second guild, a graduate of the law faculty of the Imperial St. Petersburg University , was chairman of the All-Ukrainian State Bank, then worked in the People’s Commissariat. Mother, Rachel Solomonovna Khatsrevina (1890-1967), worked as a dentist.

Early youth fell on difficult war years. He worked at a military factory, attended an evening school for working youth.

In the fall of 1944 he entered the first year at the Moscow Aviation Institute . In February 1946, he transferred to the second year of the Engineering Physics Department of the Moscow Mechanical Institute (subsequently MEPhI ).

He graduated from Moscow Engineering Physics Institute in 1950 with honors. At the same time, he passes L. D. Landau all the exams of the famous "theoretical minimum." L.D. Landau invites him to his graduate school.

Upon graduation, Kagan received a referral to one of the facilities of the Atomic Project - the Ural Gas Diffusion Plant (Novouralsk). For 6 years (from 1950 to 1956), Yu. M. Kagan has been working in the Central Laboratory of the plant, first as a junior researcher, and then as a senior researcher. During this period, he developed the general theory of the separation of isotopic gas mixtures into porous media, introducing the original idea of ​​replacing a porous medium with a heavy "wall" gas with certain scattering characteristics.

In 1954 he defended his thesis. In 1959 he defended his thesis for the degree of Doctor of Physics and Mathematics .

In 1956, Yu. M. Kagan was invited to Moscow, to the Institute of Atomic Energy (now the Kurchatov Institute ). From that time until the last days of his life, his scientific activity was connected with the Kurchatov Institute: Yu. M. Kagan headed the laboratory, was the head of the Department of Condensed Matter Theory.

For more than half a century, Yu. M. Kagan taught at the Moscow Engineering Physics Institute (since 1964 - professor). At the Department of Theoretical Nuclear Physics, he taught the author's course, "The Modern Theory of Solid State," which played an important role for many generations of students in the choice of specialization.

For many years he was a member of the editorial boards of the journals Solid State Physics, Journal of Experimental and Theoretical Physics , and Bulletin of the Russian Academy of Sciences .

The main works are devoted to the kinetic theory of gases, the theory of condensed matter , the interaction of nuclear radiation with matter, quantum kinetics at low and ultra-low temperatures.

Yu. M. Kagan develops the kinetic theory of gases with rotational degrees of freedom. Together with L.A. Maksimov, he constructed a general theory of transport phenomena in molecular gases in external fields, which made it possible, in particular, to explain the nature of the Senftleben effect, known since the 1930s (a change in the kinetic coefficients of a neutral molecular gas in a magnetic field). A vector playing a fundamental role in the theory, composed of a vector of the velocity and rotational moment of the molecule, is called the “Kagan vector”.

At the same time, he develops a consistent multiparticle theory of intransitive metals with the identification of the decisive role of the electron liquid in the formation of the statistical and dynamic properties of the metal and the emergence of a new type of features in the phonon spectrum. An important result of the theory was the removal of restrictions on the magnitude of the electron – phonon interaction constant.

This cycle is adjoined by the well-known works of Yu. M. Kagan on metallic hydrogen with proof of the existence of a metastable phase and an exhaustive analysis of its crystal structure, equation of state and vibrational spectrum in a wide pressure range.

A special place in the research of Yu. M. Kagan is occupied by the study of coherent phenomena in the resonant interaction of nuclear radiation with crystals, which led to the idea of ​​collective nuclear excitations delocalized over a crystal. In the works carried out jointly with A.M. Afanasyev , the effect of suppressing inelastic channels of the nuclear reaction during resonant nuclear scattering in crystals was predicted when the crystal becomes almost transparent (the Kagan-Afanasyev effect) by strongly absorbing radiation (gamma rays, neutrons).

This direction was preceded by a series of works by Yu. M. Kagan on the theory of the main solid-state aspects of the Mossbauer effect, which significantly contributed to the development of research in the country on the basis of this effect.

A significant amount of research by Yu. M. Kagan is devoted to the study of quantum kinetic phenomena in condensed matter. In their work with IM Lifshits, they first predicted that the kinetics of the phase transition at extremely low temperatures is realized through sub-barrier tunneling of growing new-phase nuclei.

A large series of works was published with the development of the theory of quantum diffusion of atomic particles in solid-state regular and irregular media, taking into account strong interaction with medium excitations and interparticle interaction.

In subsequent years, the scientific interests of Yu. M. Kagan were substantially related to the problem of Bose condensation and superfluidity in macroscopic quantum systems formed by ultracold gases. Yu. M. Kagan and his collaborators made a great contribution to the development of this rapidly developing field. So, the problem of the kinetics of the formation of a Bose condensate and long-range order from an initially purely classical gas was solved. The effect of suppressing inelastic processes during the formation of a Bose condensate was predicted.

Yu. M. Kagan joined in this cycle with an unexpected prediction of the possibility of observing the Bose condensation of excitations in stationary thermodynamically nonequilibrium systems.

Many of the results obtained by Yu. M. Kagan were included in monographs and textbooks. His work was widely recognized and initiated numerous original experimental studies.

• Wife - Tatyana Nikolaevna Virta (born 1930), a writer and translator of fiction from the Serbo-Croatian language, daughter of the writer N. E. Virta .
  • Son - Maxim Yuryevich Kagan (born 1961), theoretical physicist, corresponding member of the Russian Academy of Sciences.
• Brother - Boris Moiseevich Kagan (1918–2013), scientist and designer in the field of automation and computer engineering, doctor of technical sciences, professor, Stalin Prize laureate (1949).
• Sister - Elena Moiseevna Kagan (literary pseudonym Elena Rzhevskaya, 1919-2017), writer, author of well-known books about the war.
• Cousins ​​- writer Zakhar Lvovich Khatsrevin , engineer Naum Aleksandrovich Rogovin , chemist Zakhar Alexandrovich Rogovin , actress Valentina Grigoryevna Vagrina .

• 1976 - USSR State Prize of 1976 in the field of science and technology - for a series of works on predicting, detecting and studying the effect of suppressing a nuclear reaction in perfect crystals ^[1]
• 1986 - Lenin Prize of 1986 in the field of science and technology - for the series of works “Tunnel transport of matter and quantum crystallization” published in 1972-1984 ^[2]
• 1996 - Order of Friendship - for services to the state, great personal contribution to the development of the nuclear industry and many years of conscientious work ^[3]
• 1998 - Order "For Merit to the Fatherland" III degree - for merits to the state and a great personal contribution to the development of domestic science ^[4]
• 2008 - Order of Honor - for a great contribution to the development of domestic science and many years of fruitful activity ^[5]
• 2016 - Medal "For Merits in the Development of Atomic Energy" - for his great contribution to the development of the nuclear industry and many years of diligent work ^[6]
• Two Orders of the Red Banner of Labor

• 1970 - elected corresponding member of the USSR Academy of Sciences
• 1975 - Prize to them. M.V. Lomonosov Academy of Sciences of the USSR
• 1984 - elected academician of the USSR Academy of Sciences
• 1990 - Honorary Doctor of Munich Technical University (Germany)
• 1990 - Honorary Van der Waals Professor, University of Amsterdam (Netherlands)
• 1994 - Karpinsky Prize (Germany)
• 1994 - Humboldt Foundation Prize
• 1995 - elected a member of the European Academy (Academia Europaea)
• 1996 - Honorary Doctor of Uppsala University (Sweden)
• 1998 - Elected Honorary Member of the Hungarian Academy of Sciences
• 2009 - Demidov Prize
• 2017 - Prize named after I. Ya. Pomeranchuk

Yu. M. Kagan was twice invited by Harvard University to give the prestigious Lectures by Morris Loeb in physics (1988, 1996)

• A.F. Andreev , S.T. Belyaev , E.P. Velikhov , L.P. Gorkov , M.V. Kovalchuk , L.A. Maksimov , Yu. A. Osipyan , L.P. Pitaevsky , A. Yu. Rumyantsev , V. B. Timofeev , N. A. Chernoplekov , G. M. Eliashberg . Yuri Moiseevich Kagan (on the occasion of his 80th birthday) // UFN . - 2008 . - T. 178 , no. 7 .
• Hramov Yu. A. Kagan, Yuri Moiseevich // Physicists: Biographical Reference / Ed. A.I. Akhiezer . - Ed. 2nd, rev. and add. - M .: Nauka , 1983 .-- S. 123 .-- 400 p. - 200,000 copies. (per.)

• Profile of Yuri Moiseevich Kagan on the official website of the RAS
• Yuri Moiseevich Kagan // International Biographical Center
• Yuri Moiseevich Kagan // Scientific Russia Portal
• One of the last participants in the Soviet atomic project died // NG-Science , 06/04/2019