Alexander Kuzemsky

From Wikipedia, the free encyclopedia

Alexander L. Kuzemsky
Alexander L. Kuzemsky

Alexander Leonidovich Kuzemsky (Russian: Алекса́ндр Леони́дович Ку́земский) (born 1944, Ukraine) is a Russian (and former Soviet) theoretical physicist [1].

Kuzemsky studied physics at the 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 D. N. Zubarev) and Doctor Sci. 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 [2].

He worked on the variety of actual and notable topics of the statistical physics and condensed matter physics: nonequilibrium statistical mechanics[3], quantum many-body theory[4], quantum theory of magnetism[5], theory of scattering of slow neutrons in magnets[6], superconductivity[7], theory of magnetic semiconductors[8] and notable theory of the magnetic polaron[9], high-temperature superconductivity in layered compounds[10], etc. Kuzemsky formulated notable Irreducible Green Functions Method (IGFM)] [11] 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[12].

Moreover, it provides a very compact and self-consistent way of taking into account the damping effects and finite lifetimes of quasi-particles due to inelastic collisions. In addition, it correctly defines the Generalized Mean Field (GMF), that determine elastic scattering renormalizations and, in general, are not functionals of the mean particle densities only. Applications to the lattice fermion models such as Hubbard/Anderson models[13] and to the Heisenberg model of ferro- and antiferromagnet[14], which manifest the operational ability of the method were given. It was shown that the IGF method provides a powerful tool for the construction of essentially new dynamical solutions for strongly interacting many-particle systems with complex spectra. Kuzemsky derived a new self-consistent solution of the Hubbard model in the (1973-1978)[15], a notable contribution to the theory of strongly correlated electron systems. He also published a notable work on the quantum protectorate[16]. Some physical implications involved in a new concept, termed the "quantum protectorate" (QP), were developed and discussed. This was done by considering the idea of quantum protectorate in the context of quantum theory of magnetism. It was suggested that the difficulties in the formulation of quantum theory of magnetism at the microscopic level, that are related to the choice of relevant models, can be understood better in the light of the QP concept . It was argued that the difficulties in the formulation of adequate microscopic models of electron and magnetic properties of materials are intimately related to dual, itinerant and localized[17] behaviour of electrons. A criterion of what basic picture describes best this dual behaviour was formulated. The main suggestion was that quasi-particle excitation spectra might provide distinctive signatures and good criteria for the appropriate choice of the relevant model. He formulated also a succesive and notable theory of spin relaxation and diffusion in solids[18] based on the approach of the nonequilibrium statistical operator of D.N.Zubarev.

He has authored or co-authored more than 160 notable publications [19] on statistical physics and condensed matter theory.