Generalized mean fields and quasi-particle interactions in the Hubbard model

Kuzemsky, A. L.

doi:10.1007/bf02722462

Cited by 14 publications

(52 citation statements)

References 34 publications

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“…In order to calculate the mass operator self-consistently we shall use the "pair" approximation [17], [22] for the M ee and approximation of two interacting modes for M e−m and M e−ph [5], [28]. Then the corresponding expressions can be written as…”

Section: Charge Dynamics Of D-f Modelmentioning

confidence: 99%

Spectral Properties of the Generalized Spin-Fermion Models

2017

Statistical Mechanics and the Physics of Many-Particle Model Systems

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In order to account for competition and interplay of localized and itinerant magnetic behaviour in correlated many body systems with complex spectra the various types of spin-fermion models have been considered in the context of the Irreducible Green's Functions (IGF) approach. Examples are generalized d − f model and KondoHeisenberg model. The calculations of the quasiparticle excitation spectra with damping for these models has been performed in the framework of the equation-of-motion method for two-time temperature Green's Functions within a non-perturbative approach. A unified scheme for the construction of Generalized Mean Fields (elastic scattering corrections) and self-energy (inelastic scattering) in terms of the Dyson equation has been generalized in order to include the presence of the two interacting subsystems of localized spins and itinerant electrons. A general procedure is given to obtain the quasiparticle damping in a self-consistent way. This approach gives the complete and compact description of quasiparticles and show the flexibility and richness of the generalized spin-fermion model concept.

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Section: Charge Dynamics Of D-f Modelmentioning

confidence: 99%

Spectral Properties of the Generalized Spin-Fermion Models

2017

Statistical Mechanics and the Physics of Many-Particle Model Systems

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“…It becomes clear that only a thorough experimental and theoretical investigation of quasiparticle many-body dynamics of the many-particle systems can provide an answer to the relevant microscopic picture [22]. In our works, we discussed the microscopic view of a dynamic behaviour of various interacting manybody systems on a lattice [22,[30][31][32][33][34][35][36][37][38][39][40]. A comprehensive description of transition and rare-earth metals and alloys and other materials (as well as efficient predictions of properties of new materials) is possible only in those cases, where there is an adequate quantum-statistical theory based on the information about the electron and crystalline structures.…”

Section: Introductionmentioning

confidence: 99%

“…The source of difficulties here lies not only in the complexity of calculations of certain dynamic properties (such as, the density of states, electrical conductivity, susceptibility, electron-phonon spectral function, the inelastic scattering cross section for slow neutrons), but also in the absence of a well-developed method for a consistent quantum-statistical analysis of a many-particle interaction in such systems. A self-consistent field approach was used in the papers [22,[30][31][32][33][34][35][36][37][38][39][40] for description of various dynamic characteristics of strongly correlated electronic systems. It allows one to consistently and quite compactly compute quasiparticle spectra for many-particle systems with strong interaction taking into account damping effects.…”

Section: Introductionmentioning

confidence: 99%

Quasiaverages, symmetry breaking and irreducible Green functions method

Kuzemsky¹

2010

Condens. Matter Phys.

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The development and applications of the method of quasiaverages to quantum statistical physics and to quantum solid state theory and, in particular, to quantum theory of magnetism, were considered. It was shown that the role of symmetry (and the breaking of symmetries) in combination with the degeneracy of the system was reanalyzed and essentially clarified within the framework of the method of quasiaverages. The problem of finding the ferromagnetic, antiferromagnetic and superconducting "symmetry broken" solutions of the correlated lattice fermion models was discussed within the irreducible Green functions method. A unified scheme for the construction of generalized mean fields (elastic scattering corrections) and self-energy (inelastic scattering) in terms of the equations of motion and Dyson equation was generalized in order to include the "source fields". This approach complements previous studies of microscopic theory of antiferromagnetism and clarifies the concepts of Neel sublattices for localized and itinerant antiferromagnetism and "spin-aligning fields" of correlated lattice fermions. 05.30.Fk,

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“…These includes as workable patterns single-impurity Anderson model (SIAM) and Hubbard model. Recently, a lot of effort has been made to gain a better insight into the dynamical properties of the Anderson/Hubbard model [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16], especially in the context of many impurities case (e.g. [6]).…”

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confidence: 99%

“…Mere we shall use this identity as a basis for a new nnonnperturbative solution of SIAM in a wide range of temperatures and parameters of the model. We shall use the irreducible Green functions (IGF) method for the strongly correlated electronic systems [10,11] too. In paper [2] the calculation of GF (1) has been considered in the limit of infinitely strong Coulomb correlation U.…”

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confidence: 99%

Spectral Properties and New Interpolating Solution of Anderson Model

Kuzemsky

1997

Acta Phys. Pol. A

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A new approach to many-body quasiparticle dynamics of the Anderson impurity model at flnite temperatures is proposed in the framework of the equation-of-motion method. We flnd a new exact identity, which relates the one-particle and many-particle Green functions. Using this identity, it is shown that a new interpolating approximation for the one-particle Green function can be constructed. The approximation which simultaneously reproduces tle weak-coupling limit and the strong coupling limit can be formulated self-consistently. This approach offers a new method for a systematic construction of the approximate interpolating dynamical solutions of strongly correlated electron models.PACS numbers: 67.40. Db, 71.28.+d, 75.20.Hr The problem of an adequate description of strongly correlated electron systems has been studied intensively for the last decade, especially in the context of heavy fermions and high-Τ superconductivity [1]. Theoretical description of strongly correlated electron systems involves simplifled model Hamiltonian. These includes as workable patterns single-impurity Anderson model (SIAM) and Hubbard model. Recently, a lot of effort has been made to gain a better insight into the dynamical properties of the Anderson/Hubbard model [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16], especially in the context of many impurities case (e.g. [6]). This field is quite important for description of magnetic properties of anomalous rare-earth compounds [8]. The problem of an adequate and consistent description of dynamics of single-impurity and twoimpurity Anderson models (SIAM and TIAM) and other models of correlated 1attice electrons has not been fully analytically solved yet. The present paper is primarily devoted to the analysis of the relevant many-body dynamical solution of the SIAM and its correct functional structure. We wish to determine which solution actually arises from both the self-consistent many-body approach and intrinsic nature of the model itself. The Hamiltonian of SIAM has the standard form. We will consider single-particle GF of localized electrons. To improve (355) '

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Generalized mean fields and quasi-particle interactions in the Hubbard model

Cited by 14 publications

References 34 publications

Spectral Properties of the Generalized Spin-Fermion Models

Spectral Properties of the Generalized Spin-Fermion Models

Quasiaverages, symmetry breaking and irreducible Green functions method

Spectral Properties and New Interpolating Solution of Anderson Model

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