Ground state of the half-filled extended Hubbard model beyond the Hartree-Fock approximation

1984 ◽  
Vol 102 (7) ◽  
pp. 323-326 ◽  
Author(s):  
A.M. Oleś ◽  
R. Micnas ◽  
S. Robaszkiewicz ◽  
K.A. Chao
Keyword(s):  
Hubbard Model ◽  
Ground State ◽  
Extended Hubbard Model ◽  
Hartree Fock

Rigorous eta -pairing ground state in an extended Hubbard model

1995 ◽  
Vol 28 (12) ◽  
pp. 3417-3420
Author(s):  
Z J Wang ◽  
X M Qiu ◽  
X B Zhou
Keyword(s):  
Hubbard Model ◽  
Ground State ◽  
Extended Hubbard Model

GROUND STATE OF THE 2D EXTENDED HUBBARD MODEL WITH MORE THAN NEAREST-NEIGHBOR INTERACTIONS

2012 ◽  
Vol 26 (29) ◽  
pp. 1250156 ◽  
Author(s):  
S. HARIR ◽  
M. BENNAI ◽  
Y. BOUGHALEB
Keyword(s):  
Phase Diagram ◽  
Hubbard Model ◽  
Ground State ◽  
State Energy ◽  
Nearest Neighbor ◽  
Finite Size ◽  
Square Lattice ◽  
Extended Hubbard Model ◽  
Eigenvalues And Eigenvectors ◽  
Repulsion Energy

We investigate the ground state phase diagram of the two dimensional Extended Hubbard Model (EHM) with more than Nearest-Neighbor (NN) interactions for finite size system at low concentration. This EHM is solved analytically for finite square lattice at one-eighth filling. All eigenvalues and eigenvectors are given as a function of the on-site repulsion energy U and the off-site interaction energy Vij. The behavior of the ground state energy exhibits the emergence of phase diagram. The obtained results clearly underline that interactions exceeding NN distances in range can significantly influence the emergence of the ground state conductor–insulator transition.

The Ground State Energy of the Hubbard Model in Hubbard's Approximation

1972 ◽  
Vol 27 (6) ◽  
pp. 889-893 ◽  
Author(s):  
Rainer Jelitto
Keyword(s):  
Hubbard Model ◽  
Ground State Energy ◽  
Ground State ◽  
State Energy ◽  
Magnetic Ordering ◽  
Coupling Constant ◽  
Hartree Fock ◽  
The Best Approximation ◽  
Paramagnetic Solution ◽  
Neighbour Interaction

Abstract We have calculated the ground state energy of the Hubbard model in the approximation of Hubbard's first paper1 . For the neutral model with nearest neighbour interaction the energy resulting from the selfconsistent paramagnetic solution is compared with those ones following from the (ferromagnetic) Hartree-Fock and an (antiferromagnetic) single particle theory. The energy of the latter one turns out to be the best approximation of the true ground state energy of the model for all values of the coupling constant V0 , but the energy derived from Hubbard's approximation, in spite of the absence of magnetic ordering, is a reasonable approximation at least for sufficiently large values of V0.

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