Alexander Leonidovich Kuzemsky (; born 1944) is a Russian (and former Soviet) theoretical physicist. Biography Kuzemsky studied physics at the Faculty of Physics in Moscow State University (1963—1969). He received B.Sc. degree in 1969 (promotor professor L. A. Maksimov, correspondent member of Russian Academy of Sciences). Kuzemsky gained his Ph.D. in theoretical and mathematical physics in 1970 (promotor professor Dmitry Zubarev) and Doctor of Sciences degree in theoretical and mathematical physics in 1985. Both degrees were obtained from the Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, Dubna where he is a staff member since 1969. He is currently a leading researcher at the Bogoliubov Laboratory of Theoretical Physics. Research Kuzemsky worked on the variety of actual and notable topics of the statistical physics and condensed matter physics: nonequilibrium statistical mechanics quantum many-body theory quantum theory of magnetism theory of scattering of slow neutrons in magnets, superconductivity theory of magnetic semiconductors and notable theory of the magnetic polaron high-temperature superconductivity in layered compounds etc. In series of his works the development of methods of quantum statistical mechanics was considered in light of their applications to quantum solid-state theory. He discussed fundamental problems of the physics of magnetic materials and the methods of the quantum theory of magnetism, including the method of two-time temperature Green's functions which is widely used in various physical problems of many-particle systems with interaction. Quantum cooperative effects and quasi-particle dynamics in the basic microscopic models of quantum theory of magnetism: the Heisenberg model, the Hubbard model, the Anderson Model, and the spin-fermion model were considered in the framework of novel self-consistent-field approximation. A comparative analysis of these models was presented; in particular, their applicability for description of complex magnetic materials was compared. Kuzemsky formulated notable Irreducible Green Functions Method (IGFM) for the systems with complex spectrum and strong interaction. The Green-function technique, termed the irreducible Green function method is a certain reformulation of the equation-of motion method for double-time temperature dependent Green functions. This advanced and notable method was developed to overcome some ambiguities in terminating the hierarchy of the equations of motion of double-time Green functions and to give a workable technique to systematic way of decoupling. The approach provides a practical method for description of the many-body quasi-particle dynamics of correlated systems on a lattice with complex spectra. Moreover, this method provides a very compact and self-consistent way of taking into account the