Igor Tamm
Name in native script: Игорь Тамм
1895–1971, Vladivostok, Russian Empire, Moscow, Soviet Union
Russian theoretical physicist who, with Ilya Frank, explained Cherenkov radiation, winning the 1958 Nobel Prize in Physics.
Born in Vladivostok, Tamm studied in Edinburgh and at Moscow University before becoming one of the pillars of Soviet theoretical physics. He founded the theoretical department at the Lebedev Physical Institute in 1934 and trained generations of Soviet physicists, while also teaching at Moscow State University.
Beyond the Nobel-winning theory of Cherenkov radiation, he identified surface bound states (Tamm states), developed quantum methods for nuclear interactions, and, with Andrei Sakharov, proposed the tokamak magnetic-confinement reactor in 1950–1951. He was also renowned for his democratic convictions, intervening on behalf of persecuted scientists.
Nobel-winning work
In 1937, with Ilya Frank, Tamm built the classical electrodynamical theory of the blue light Cherenkov had observed. They proved that a charge moving uniformly through a dielectric medium radiates if its velocity exceeds the phase velocity of light c/n in that medium.
The radiation is emitted coherently on a cone whose opening angle satisfies cos θ = c/(nv) — an optical shock wave. This formula lets one infer a particle's velocity from the emission angle, turning the Cherenkov effect into an irreplaceable instrument for measuring and identifying particles in high-energy physics.
Workplaces: Lebedev Physical Institute, Moscow State University
Russia