Yuri Borisovich Rumer (Russian : Юрий Борисович Румер, 28 April 1901 – 1 February 1985) was a Soviet theoretical physicist, who mostly worked in the fields of quantum mechanics and quantum optics. Known in the West as Georg Rumer, he was a close friend of Lev Landau, and was arrested with him during the Great Purge in 1938.