Tamm, Igor Evgenyevich

Igor Evgenyevich Tamm (8.07.1895-12.04.1971) —a Soviet theoretical physicist, academician (1953; corresponding member 1933). Born in Vladivostok. He graduated from Moscow University (1918), taught physics at the Crimean University (1919—20) and the Odessa Polytechnic Institute (1921-22). In 1922 he moved to Moscow. In 1924—41 he worked at Moscow University (from 1930 as professor and head of the chair of theoretical physics), and from 1934 was head of the theoretical department of the Physical Institute of the USSR Academy of Sciences (now the I. E. Tamm Department of Theoretical Physics). In 1945 he organised the chair at the Moscow Engineering Physics Institute and for a number of years was its head, and then in 1954-57 he was professor at Moscow University. His work was devoted to classical electrodynamics, quantum mechanics, the theory of the solid state, physical optics, nuclear physics, the theory of elementary particles, the problem of thermonuclear fusion, and applied physics. In 1930 he constructed a complete quantum theory of the scattering of light in crystals, for which he carried out the quantisation not only of light waves but also of elastic waves in a solid, introducing the concept of sound quanta, or phonons. He gave (1930) a consistent derivation of the Klein — Nishina formula for the scattering of light by an electron, which was of great importance for establishing Dirac's relativistic wave equation for the electron. In doing so he was the first to propose a new method of calculation in the perturbation theory of a particle, which greatly eases the calculations. Applying quantum mechanics to the theory of metals, he showed (1932) the possibility of special states of electrons on the surface of crystals (Tamm levels), and together with S. L. Shubin laid the foundations of the quantum-mechanical theory of the photoelectric effect in metals (1931). Together with D. D. Ivanenko he constructed (1934) one of the first field theories of nuclear forces, in which he first showed the possibility of the transfer of interactions by particles of finite mass. Already in 1935 H. Yukawa, starting from the Tamm — Ivanenko theory, predicted the existence of the meson as the carrier of these forces. In 1934, together with S. A. Altshuler, he put forward the idea that the neutron has a magnetic moment, and with L. I. Mandelstam he gave a more general interpretation of Heisenberg's uncertainty relation in terms of “energy — time”. In 1937, together with I. M. Frank, he developed the theory of the radiation of an electron moving in a medium at a speed exceeding the phase velocity of light in that medium — the theory of the Vavilov — Cherenkov effect (USSR State Prize, 1946; Nobel Prize, 1958). In the post-war years he was the first to begin research on the problem of thermonuclear fusion. In 1950 he put forward the idea of the thermal insulation of hot plasma by a strong magnetic field and of the magnetic thermonuclear reactor. His work was also devoted to the problem of the interaction of relativistic particles. In 1945 he gave an approximate method of treating particles, different from the method of perturbation theory (the Tamm — Dancoff method). In the 1960s he strove to construct a theory of elementary particles that included an elementary length. Hero of Socialist Labour (1953). USSR State Prizes (1946, 1953). M. V. Lomonosov Gold Medal (1968). He founded a school of theoretical physicists (V. L. Ginzburg, M. A. Markov. S. A. Altshuler, D. I. Blokhintsev, E. L. Feinberg, A. S. Davydov, S. I. Petr, L. V. Keldysh, E. S. Fradkin, S. Z. Belenky, A. D. Galanin, D. A.Kirzhnits, V. Ya. Fainberg, V. P. Silin and others.) Member of a number of academies of sciences and scientific societies.