TAMM, IGOR YEVGENYEVICH (1895–1971), Russian physicist and Nobel Laureate. Tamm was born in Vladivostok and graduated in physics from Moscow University (1918). He worked in different universities and institutes in Moscow and the Crimea including the Moscow State University (1924–37). He was appointed professor and head of the theoretical division of the P.N. Lebedev Institute of Physics of the (then) U.S.S.R. Academy of Sciences (1934–71). Tamm was a theoretical physicist whose early work concerned light and quantum theory. He is best known for his explanation of the Cerenkov effect, the blue glow produced by charged particles from radioactive decay when these penetrate fluids. Tamm showed that the effect is attributable to a "bow wave" of photons created by fast particles exceeding the speed of light in a fluid medium. This explanation did not simply explain an aesthetically beautiful phenomenon but had implications for the subsequent progress of particle physics including the discovery of anti-protons. He was awarded the 1958 Nobel Prize in physics for this discovery, shared with Pavel Cherenkov and Il'ja Frank. Subsequently he continued his work on the theory of light, transistors, the nature of showers in cosmic rays, and, in collaboration with Andrei Sakharov, methods for controlling thermonuclear fusion reactions. He also collaborated closely with Professor L. Mandelstam between 1920 and 1944. Tamm's honors include election to the (then) U.S.S.R. Academy of Sciences (1953), the American Academy of Arts and Sciences, and the Swedish Physical Society, and also the State Prize of the former U.S.S.R. (1946) and the title of Hero of Socialist Labor.