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:Kuzemsky, A. L. Works on Statistical Physics and Quantum Theory of Solid State. JINR Publishing, Dubna, 2009. [in Russian] nonequilibrium statistical mechanicsKuzemsky, A. L. Theory of Transport Processes and the Method of the Nonequilibrium Statistical Operator. Int. J. Modern Phys. B21(2007):2821-2949, quantum many-body theoryKuzemsky, A. L. Statistical Mechanics and the Physics of Many-Particle Model Systems, Phys. Part. Nucl. 40 (2009):949-997, quantum theory of magnetismMaksimov, L. A., Kuzemsky, A. L. On the Theory of the Ferromagnetic Crystal with Two Spins per Site, Physics of Metals and Metallography, 31 (1971):1,Kuzemsky, A. L., Marvakov, D., Spectrum of Excitations of the Heisenberg Antiferromagnet at Finite Temperatures,Theor. Math. Phys. 83 (1990):147,Kuzemsky, A. L. Itinerant Antiferromagnetism of Correlated Lattice Fermions,Physica A267 (1999):131,Kuzemsky, A. L. Spectral Properties of the Generalized Spin-Fermion Models. Int. J. Modern Phys. B13(1999):2573, theory of scattering of slow neutrons in magnets,Kuzemsky, A. L. Neutron Scattering and Magnetic Properties of Transition Metals and Their Alloys, Sov. J. Part. Nucl. 12 (1981):146, superconductivityKuzemsky, A. L. et al.,Equations of Superconductivity for Transition Metals in the Wannier Representation,Theor. Math. Phys. 53 (1982):138,Kuzemsky, A. L. et al.,Electron-Phonon Interaction in Disordered Transition Metal Alloys,phys. stat. sol. (b) 113 (1982):409,Kuzemsky, A. L. et al.,Self-Consistent Theory of an Electron-Phonon Interaction in Transition Metals and Their Compounds,Physica. B122 (1983):168,Kuzemsky, A. L. et al.,The Theory of Strong Coupling Superconductivity in Disordered Transition Metal Alloys,J. of Low Temp. Phys. 52 (1983):81 theory of magnetic semiconductors and notable theory of the magnetic polaronKuzemsky, A. L. et al.,The Self-Consistent Theory of Elementary Excitations in System with Many-Branch Quasiparticle Spectra(Ferromagnetic Semiconductors),J.Physics C: Solid State Phys., 18 (1985):2871,Kuzemsky, A. L. et al.,A Self-consistent Theory of the Magnetic Polaron,Physica B+C. 138 (1986):129,Kuzemsky, A. L.,Bound and Scattering State of Itinerant Charge Carriers in Complex Magnetic Materials,Int. J. Modern Phys. B18 (2004):3227,Kuzemsky, A. L., Role of Correlation and Exchange for Quasiparticle Spectra of Magnetic and Diluted Magnetic Semiconductors,Physica. B355 (2005):318 high-temperature superconductivity in layered compoundsKuzemsky, A. L. and Kuzemskaya I. G.,Structural Sensitivity of Superconducting Properties of Layered Systems,Physica. C383 (2002):140,Kuzemsky, A. L. and Kuzemskaya I. G.,The Structural, Superconducting, and Transport Properties of the Mercurocuprates and Other Layered Systems,in: Narlikar A., ed. Studies of High Temperature Superconductors. Nova Science Publ., New York, 2003, p.1-80 etc.
In series of his worksKuzemsky, A. L. Statistical Mechanics and the Physics of Many-Particle Model Systems, Phys. Part. Nucl. 40 (2009):949-997. 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 functionsTyablikov, S.V. Methods in the Quantum Theory of Magnetism. Plenum Press, 1967, 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)Kuzemsky, A. L.,Self-Consistent Theory of Electron Correlation in the Hubbard Model,Theor.Math.Phys. 36 (1978):208,Kuzemsky, A. L.,Irreducible Green Function Method in Condensed Matter Theory,Sov.Phys.Dokl. 34 (1989):974,Kuzemsky, A. L.,Interpolation Solution of the Single-impurity Anderson Model,Phys.Lett. A153 (1991):466,Kuzemsky, A. L.,Generalized Mean Fields and Quasiparticle Interactions in the Hubbard Model,Nuovo Cimento. B109 (1994):829,Kuzemsky, A. L.,Irreducible Green Function Method and the Many-Particle Interacting Systems on a Lattice,Rivista Nuovo Cimento. 25 (2002):1,Kuzemsky, A. L.,Quasiparticle Many-Body Dynamics of the Anderson Model,Int. J. Modern Phys. B10 (1996):1895,Kuzemsky, A. L.,Quasiaverages, Symmetry Breaking and Irreducible Green Functions Method,Condensed Matter Physics 13 (2010):43001:1-20, 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 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 and to the Heisenberg model of ferro- and antiferromagnet, 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, a notable contribution to the theory of strongly correlated electron systems.
He also published a notable work on the quantum protectorate.Kuzemsky, A. L.,Quantum Protectorate and Microscopic Models of Magnetism,Int. J. Modern Phys. B16 (2002):803, Some physical implications involved in a new concept, termed the "quantum protectorate" (QP), invented by R. Laughlin and D. PinesLaughlin, R.D. and Pines, D.,Theory of Everything,Proc. Natl. Acad. Sci. (USA). 97 (2000):28, 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 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. The concepts of broken symmetry, quantum protectorate, and Bogoliubov's quasi-averages were analyzed in the context of quantum theory of magnetism and theory of superconductivity.Kuzemsky, A.L.,Bogoliubov's Vision: Quasiaverages and Broken Symmetry to Quantum Protectorate and Emergence,Int. J. Modern Phys. B24 (2010):835-935,
In this interdisciplinary study he focused on the applications of the symmetry principles to quantum and statistical physics in connection with some other branches of science. The idea of quasiaverages, formulated by N. N. Bogoliubov, gives the so-called macro-objectivation of the degeneracy in domain of quantum statistical mechanics, quantum field theory and in the quantum physics in general. He discussed there the complementary unifying ideas of modern physics, namely: spontaneous symmetry breaking, quantum protectorate and emergence.
The interrelation of the concepts of symmetry breaking, quasiaverages and quantum protectorate was analyzed in the context of quantum theory and statistical physics. The chief purposes of that study were to demonstrate the connection and interrelation of these conceptual advances of the many-body physics and to try to show explicitly that those concepts, though different in details, have a certain common features. Several problems in the field of statistical physics of complex materials and systems (e.g. the chirality of molecules) and the foundations of the microscopic theory of magnetism and superconductivity were discussed in relation to these ideas.
The notion of broken symmetry was presented also within the nonequilibrium statistical operator approach developed by D. N. Zubarev.Zubarev, D.N., Nonequilibrium Statistical Thermodynamics. Consultant Bureau, 1974, The ensemble method, as it was formulated by J. W. Gibbs, has the generality and the broad applicability to equilibrium statistical mechanics. Different macroscopic environmental constraints lead to different types of ensembles, with particular statistical characteristics.
The nonequilibrium statistical operator methodZubarev, D.N., Nonequilibrium Statistical Thermodynamics. Consultant Bureau, 1974,Kuzemsky, A. L. Theory of Transport Processes and the Method of the Nonequilibrium Statistical Operator. Int. J. Modern Phys. B21(2007):2821-2949, permits one to generalize the Gibbs ensemble method to the nonequilibrium case and to construct a nonequilibrium statistical operator which enables one to obtain the transport equations and calculate the transport coefficients in terms of correlation functions, and which, in the case of equilibrium, goes over to the Gibbs distribution. In the framework of the latter approach the derivation