Dmitri Dmitrievich Ivanenko (; July 29, 1904 – December 30, 1994) was a Ukrainian theoretical physicist who made great contributions to the physical science of the twentieth century, especially to nuclear physics, field theory, and gravitation theory. He worked in the Poltava Gravimetric Observatory of the Institute of Geophysics of NAS of Ukraine, was the head of the Theoretical Department Ukrainian Physico-Technical Institute in Kharkiv, Head of the Department of Theoretical Physics of the Kharkiv Institute of Mechanical Engineering. Professor of University of Kharkiv, Professor of Moscow State University (since 1943). Biography Dmitri Ivanenko was born on July 29, 1904, in Poltava, where he finished school, in 1920-1923 he studied at the Poltava Pedagogical Institute and began his creative path as a teacher of physics in middle school. Then D. D. Ivanenko studied at Kharkiv University, from which in 1923 he was transferred to Petrograd University. In 1926, while still a student, he wrote his first scientific works: with George Gamow on the Kaluza–Klein five-dimensional theory and with Lev Landau on the problems of relativistic quantum mechanics. After graduating from the university, from 1927 to 1930 D. Ivanenko was a scholarship student and then a research scientist at the Physical Mathematical Institute of Academy of Sciences of the USSR. During these years he collaborated with Lev Landau, Vladimir Fock and Viktor Ambartsumian, later becoming famous. This was when modern physics, the new quantum mechanics, and nuclear physics were established. In 1928, Ivanenko and Landau developed the theory of fermions as skew-symmetric tensors. This theory, known as the Ivanenko-Landau-Kahler theory, is not equivalent to Dirac's one in the presence of a gravitation field, and only it describes fermions on a lattice. In 1929, Ivanenko and Fock described the parallel displacement of spinors in curved space-time (the famous Ivanenko–Fock coefficients). Nobel laureate Abdus Salam called it the first gauge field theory. In 1930, Ambartsumian and Ivanenko suggested the hypothesis of creation of massive particles (1930) which is a cornerstone of contemporary quantum field theory. From 1929 to 1931 D. Ivanenko worked at the Ukrainian Physico-Technical Institute in Kharkiv, being the first director of its theoretical division. Ivanenko was one of organizers of the first Soviet theoretical conference (1929) and the new journal Physikalische Zeitschrift der Sowjetunion. After returning to Leningrad at the Physical-Technical Institute, D. Ivanenko concentrated his interest to nuclear physics. In 1932 Ivanenko proposed the proton-neutron model of the atomic