Hubbard Model as the Simplest Model of Strong Electron Correlation Multielectron Models in X-Operators Representation General Approach to the Quasiparticle Description of Strongly Correlated Systems Unitary Transformations Method in Atomic Representation Diagram Technique in the X-Operators Representation Spectral Properties of the Anisotropic Metallic Ferromagnets Peculiarities of the de Haas-van Alphen Effect in Strongly Correlated Systems with Magnetic Polaron States The Electronic Structure of Copper Oxides in the Multiorbital p-d ModelHubbard Model as the Simplest Model of Strong Electron Correlation Multielectron Models in X-Operators Representation General Approach to the Quasiparticle Description of Strongly Correlated Systems Unitary Transformations Method in Atomic Representation Diagram Technique in the X-Operators Representation Spectral Properties of the Anisotropic Metallic Ferromagnets Peculiarities of the de Haas-van Alphen Effect in Strongly Correlated Systems with Magnetic Polaron States The Electronic Structure of Copper Oxides in the Multiorbital p-d Model

IMPERIAL COLLEGE PRESS eBooksJan 1, 200484 citations

Coherent state path integral approach to correlated electron systems with deformed Hubbard operators: from Fermi liquid to Mott insulator

Xiao-Yong Feng, Jianhui Dai

In strongly correlated electron systems the constraint which prohibits the double electron occupation at local sites can be realized by either the infinite Coulomb interaction or the correlated hopping interaction described by the Hubbard operators, but they both render the conventional field theory inapplicable. Relaxing such the constraint leads to a class of correlated hopping models based on the deformed Hubbard operators which smoothly interpolate the locally free and strong coupling limits by a tunable interaction parameter $0\leq λ\leq 1$ . Here we propose a coherent state path integral approach appropriate to the deformed Hubbard operators for {\it arbitrary} $λ$ . It is shown that this model system exhibits the correlated Fermi liquid behavior characterized by the enhanced Wilson ratio for all $λ$ . It is further found that in the presence of on-site Coulomb interaction a finite Mott gap appears between the upper and lower Hubbard bands, with the upper band spectral weight being heavily reduced by $λ$ . Our approach stands in general spatial dimensions and reveals an unexpected interplay between the correlated hopping and the Coulomb repulsion.In strongly correlated electron systems the constraint which prohibits the double electron occupation at local sites can be realized by either the infinite Coulomb interaction or the correlated hopping interaction described by the Hubbard operators, but they both render the conventional field theory inapplicable. Relaxing such the constraint leads to a class of correlated hopping models based on the deformed Hubbard operators which smoothly interpolate the locally free and strong coupling limits by a tunable interaction parameter $0\leq λ\leq 1$. Here we propose a coherent state path integral approach appropriate to the deformed Hubbard operators for {\it arbitrary} $λ$. It is shown that this model system exhibits the correlated Fermi liquid behavior characterized by the enhanced Wilson ratio for all $λ$. It is further found that in the presence of on-site Coulomb interaction a finite Mott gap appears between the upper and lower Hubbard bands, with the upper band spectral weight being heavily reduced by $λ$. Our approach stands in general spatial dimensions and reveals an unexpected interplay between the correlated hopping and the Coulomb repulsion.

arXiv:1904.12499Apr 29, 20190 citations

Quantum phenomena in strongly correlated electron systems

Pavel V. Shevchenko

Sep 1, 19990 citations

Electronic spectrum and superconductivity in Hubbard model

Плакида, Oudovenko

A microscopic theory of electronic spectrum and superconducting pairing within the Hubbard model is formulated.The Dyson equation for the normal and anomalous Green functions in terms of the Hubbard operators is derived by applying the Mori-type projection technique.The self-energy is evaluated in the noncrossing approximation for electron scattering on spin and charge fluctuations induced by kinematic interaction for Hubbard operators.Numerical results for electron dispersion in the strong correlation limit are presented.Superconducting pairing mediated by antiferromagnetic exchange and spin fluctuations is discussed.A microscopic theory of electronic spectrum and superconducting pairing within the Hubbard model is formulated.The Dyson equation for the normal and anomalous Green functions in terms of the Hubbard operators is derived by applying the Mori-type projection technique.The self-energy is evaluated in the noncrossing approximation for electron scattering on spin and charge fluctuations induced by kinematic interaction for Hubbard operators.Numerical results for electron dispersion in the strong correlation limit are presented.Superconducting pairing mediated by antiferromagnetic exchange and spin fluctuations is discussed.

Condensed Matter PhysicsSep 1, 20080 citations

Self-consistent theory of electron correlation in the Hubbard model

A. L. Kuzemskii

Theoretical and Mathematical PhysicsAug 1, 197815 citations

0\leq λ\leq 1

. Here we propose a coherent state path integral approach appropriate to the deformed Hubbard operators for {\it arbitrary}

λ

. It is shown that this model system exhibits the correlated Fermi liquid behavior characterized by the enhanced Wilson ratio for all

λ

. It is further found that in the presence of on-site Coulomb interaction a finite Mott gap appears between the upper and lower Hubbard bands, with the upper band spectral weight being heavily reduced by

λ

. Our approach stands in general spatial dimensions and reveals an unexpected interplay between the correlated hopping and the Coulomb repulsion.