Arkady Beinusovich Migdal (born 11.03.1911) is a Soviet theoretical physicist and an academician (1966; corresponding member 1953). He was born in Lida (now in Grodno Region). He graduated from Leningrad University (1936). In 1943 — 45 he worked at the Institute of Physical Problems of the USSR Academy of Sciences, in 1945-71 at the Kurchatov Institute of Atomic Energy, and since 1971 he has worked at the Institute of Theoretical Physics of the USSR Academy of Sciences, at the same time being from 1944 a professor at the Moscow Engineering Physics Institute.
His work concerned atomic and nuclear physics, quantum field theory, the theory of metals and other problems of modern theoretical physics. Together with L. D. Landau he created a new line of research in theoretical physics — the application of the methods of quantum field theory to the many-body problem. He was the first to treat correctly the interaction of electrons with lattice vibrations (phonons) in normal metals and established a number of consequences that arise when this interaction is taken into account. He proved the existence of a jump in the momentum distribution of Fermi particles for systems with any interaction and extended the methods of the theory of the Fermi liquid to systems of finite size.
Applying the methods of many-body theory in nuclear physics, he obtained important results on the theory of the moments of inertia of nuclei and, using the ideas of the theory of the Fermi liquid to describe finite systems, was the first to describe quantitatively important properties of nuclei — magnetic and quadrupole moments, the isotope shift, radiative transitions and the giant resonance in photoabsorption. He constructed (1954) a rigorous quantum-electrodynamic theory of bremsstrahlung and pair production in media. In 1959 he put forward the suggestion that nuclear matter in neutron stars is a liquid in a superfluid state. A number of his papers are devoted to the study of the properties of the vacuum in strong fields. He also works on applied questions. He founded a school of physicists.