scholarly journals Non-perturbative treatment of charge and spin fluctuations in the two-dimensional extended Hubbard model: Extended two-particle self-consistent approach

2007 ◽  
Vol 76 (8) ◽  
Author(s):  
B. Davoudi ◽  
A.-M. S. Tremblay
Keyword(s):  
Hubbard Model ◽  
Spin Fluctuations ◽  
Two Dimensional ◽  
Extended Hubbard Model ◽  
Self Consistent ◽  
Consistent Approach ◽  
Perturbative Treatment

Phase diagram of the two-dimensional extended Hubbard model: pairing from charge and spin fluctuations

2005 ◽  
Vol 359-361 ◽  
pp. 518-520
Author(s):  
Seiichiro Onari ◽  
Ryotaro Arita ◽  
Kazuhiko Kuroki ◽  
Hideo Aoki
Keyword(s):  
Phase Diagram ◽  
Hubbard Model ◽  
Spin Fluctuations ◽  
Two Dimensional ◽  
Extended Hubbard Model

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′.

scholarly journals Self-consistent effective Hamiltonian theory for fermionic many-body systems

2020 ◽  
pp. 2150019
Author(s):  
Xindong Wang ◽  
Hai-Ping Cheng
Keyword(s):  
Hubbard Model ◽  
Order Parameter ◽  
Cooper Pair ◽  
Effective Hamiltonian ◽  
Two Dimensional ◽  
Body System ◽  
Many Body ◽  
Hamiltonian Theory ◽  
Self Consistent ◽  
Many Body Systems

Using a separable many-body variational wavefunction, we formulate a self-consistent effective Hamiltonian theory for fermionic many-body system. The theory is applied to the two-dimensional (2D) Hubbard model as an example to demonstrate its capability and computational effectiveness. Most remarkably for the Hubbard model in 2D, a highly unconventional quadruple-fermion non-Cooper pair order parameter is discovered.

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