Yakov Borisovich Zel'dovich
Yakov Borisovich Zeldovich (Belarusian: Я́каў Бары́савіч Зяльдо́віч, Russian: Я́ков Бори́сович Зельдо́вич; 8 March 1914 – 2 December 1987), also known as YaB, D.N. was a leading Soviet physicist, who is known for his prolific contributions in physical cosmology, physics of thermonuclear reactions, combustion, and hydrodynamical phenomena.From 1943, Zeldovich, a self-taught physicist, started his career by playing a crucial role in the development of the former Soviet program of nuclear weapons. In 1963, he returned to academia to embark on pioneering contributions on the fundamental understanding of the thermodynamics of black holes and expanding the scope of physical cosmology.
Source: Wikipedia