Efim Samoilovich Fradkin (born 24.02.1924) is a Soviet theoretical physicist and a corresponding member of the USSR Academy of Sciences (1970). He was born in the village of Shchedrino (now in Gomel Region). He graduated from Lvov University (1948). Since 1948 he has worked at the Physical Institute of the USSR Academy of Sciences.
His work concerned quantum field theory, quantum statistics, hydrodynamics, kinetics and elementary-particle physics. He found a path-integral solution for the scattering matrix of interacting particles in quantum field theory (1954) and a path-integral solution of the Dirac equation in an arbitrary external field (1965). He obtained a system of fully renormalised equations for the Green function in quantum field theory (1954), found a conformally invariant solution of these equations and, on that basis, the critical indices in the theory of second-order phase transitions (1977).
He obtained a system of equations for the Green functions of relativistic statistics and constructed a diagram technique for statistics (1958). Independently of J. Schwinger he proposed the Euclidean formulation of quantum field theory (1958). He proposed a method of generalised canonical quantisation for arbitrary relativistic Fermi and Bose gauge theories and found a path-integral solution also for theories with an open gauge algebra; on this basis he carried out the quantisation and obtained the scattering matrix for supergravity (1977) and a correct solution for the s-matrix in quantum gravity (1974).
He constructed a model of extended supergravity that unifies gravitation, electrodynamics and the gravitino (1976), and proposed unified asymptotically free models of the weak, electromagnetic and strong interactions: SU(5), E6 and E8.
State Prize (1953). The I. E. Tamm Prize (1980).