Yakov Sinai

Yakov Grigorevich Sinai is a Russian American mathematician, born in Moscow on 21 September 1935 into a Russian Jewish academic family, who is known for his work on dynamical systems. He earned his Ph.D. at Moscow State University in 1960 under Andrey Kolmogorov, and together they introduced Kolmogorov-Sinai entropy, which measures the unpredictability of a dynamical system. In 1963 he introduced dynamical billiards, known as Sinai billiards, and proved that for most initial trajectories the system is ergodic. He has also worked on mathematical physics and probability theory, including the rigorous foundations of the renormalization group method. He has won the Wolf Prize in Mathematics and the Abel Prize, and has been a professor at Princeton University since 1993 and a senior researcher at the Landau Institute for Theoretical Physics in Moscow.