Correlation Effects of Third-order Perturbation in the Extended Hubbard Model

1989 ◽  
Vol 42 (5) ◽  
pp. 565
Author(s):  
CZ Wei ◽  
HQ Nie ◽  
L Li ◽  
KY Zhang
Keyword(s):  
Hubbard Model ◽  
Electron Correlation ◽  
Spin Correlation ◽  
Order Perturbation ◽  
Atomic Electron ◽  
Nearest Neighbour ◽  
Extended Hubbard Model ◽  
Third Order ◽  
The Third ◽  
Significant Correction

Using the local approach, we have performed a third�order perturbation calculation to investigate the effects of intra-atomic electron correlation and electron and spin correlation between nearest neighbour sites in the extended Hubbard model. We found that significant correction of the third order over the second order results and, in comparison with the results of the third-order perturbation where only the intra-atomic electron correlation is included, the influence of the electron and spin correlation between nearest neighbour sites on the correlation energy is non-negligible.

LOCAL APPROACH TO VARIATIONAL METHOD FOR ELECTRON CORRELATION IN NARROW BAND SYSTEMS

1987 ◽  
Vol 01 (05n06) ◽  
pp. 1311-1320 ◽  
Author(s):  
GUO-ZHU WEI ◽  
HUI-QUAN NIE ◽  
KAI-YI ZHANG ◽  
K.A. CHAO
Keyword(s):  
Electron Correlation ◽  
Narrow Band ◽  
Correlation Effect ◽  
Second Order ◽  
Order Perturbation ◽  
Extended Hubbard Model ◽  
Perturbation Calculation ◽  
Local Approach ◽  
Third Order ◽  
Electron Correlation Effect

Using the local approach, we have performed a third order perturbation calculation to investigate the electron correlation effect in extended Hubbard model with both positive and negative intraatomic and interatomic correlation energies. We found the significant third order correction over the second order terms. Consequently, all published results, especially the phase diagrams which were derived with the second order perturbation calculation are not reliable.

TWO-DIMENSIONAL QUARTER-FILLED EXTENDED HUBBARD MODEL AT STRONG COUPLING

2005 ◽  
Vol 19 (01n03) ◽  
pp. 213-216
Author(s):  
W. F. LEE ◽  
H. Q. LIN
Keyword(s):  
Hubbard Model ◽  
Correlation Functions ◽  
Nearest Neighbor ◽  
Spin Correlation ◽  
Perturbation Approach ◽  
Effective Hamiltonian ◽  
Two Dimensional ◽  
Extended Hubbard Model ◽  
Neighbor Interaction ◽  
Electron Hopping

In this paper, we generalized the perturbation approach to study the quasi-two-dimension extended Hubbard model. This model is characterizing by intra-chain electron hopping t, on-site Column interaction U, nearest-neighbor interaction V, and inter-chain electron hopping t′ and nearest-neighbor interaction V′. An effective Hamiltonian up to sixth-order in t/U, t/V, t/V′, t′/U, t′/V and t′/V′ expansion was obtained and the spin-spin correlation functions were calculated. We presented results for t=t′, V=V′.

Quarter-Filled Extended Hubbard Model at Strong Coupling

2003 ◽  
Vol 17 (18n20) ◽  
pp. 3339-3342 ◽  
Author(s):  
W. F. Lee ◽  
H. Q. Lin
Keyword(s):  
Hubbard Model ◽  
Strong Coupling ◽  
Coulomb Interaction ◽  
State Energy ◽  
Nearest Neighbor ◽  
Spin Correlation ◽  
Perturbation Approach ◽  
Effective Hamiltonian ◽  
Extended Hubbard Model ◽  
One Dimensional

We apply a perturbation approach to study the quarter-filled extended Hubbard model at strong coupling limit. An effective Hamiltonian up to sixth order in t/U and t/V (t defines electron hopping, U defines on-site Coulomb interaction, and V defines nearest-neighbor Coulomb interaction) for one-dimensional chains was obtained. The spin-spin correlation functions were involved, which can be obtained after comparing to the ground state energy numerically obtained from the phase diagram.

scholarly journals Higher Order Perturbation Corrections of Rotating Excited States in the Standard SU(3) Skyrme Model to Baryon Mass Spectrum

1997 ◽  
Vol 12 (05) ◽  
pp. 873-890 ◽  
Author(s):  
Jin-Ping Li ◽  
Mu-Lin Yan ◽  
Rong-Hua Yu
Keyword(s):  
Experimental Data ◽  
Mass Spectrum ◽  
Excited States ◽  
Higher Order ◽  
Skyrme Model ◽  
Order Perturbation ◽  
Third Order ◽  
The Third ◽  
Baryon Mass ◽  
Higher Order Corrections

The higher order corrections of SU(3) rotating excited states to the Gell-Mann–Okubo Relations (or GOR) are presented in the standard SU(3) Skyrme model. The Improved GOR (or IGOR) are obtained. The results show the IGOR for decuplet up to the third order and for octet up to the second order are much compatible with the experimental data. But things become quite inadequate for the octet to the third order. In order to overcome the inadequacy, a heuristic discussion is presented. The properties of SU(3) rotating excited states 27-let (with spin [Formula: see text] or [Formula: see text]), 10*-let (with spin [Formula: see text]) and 35-let (with spin [Formula: see text]) are also discussed.

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