Correlated ground state of the Hubbard model

1990 ◽  
Vol 79 (3) ◽  
pp. 351-359 ◽  
Author(s):  
M. L. Ristig
Keyword(s):  
Hubbard Model ◽  
Ground State

A controlled route to the competing phases and the single-particle spectral function in the ground state of the 2D Hubbard model

2007 ◽  
Vol 460-462 ◽  
pp. 248-251
Author(s):  
Werner Hanke ◽  
Markus Aichhorn ◽  
Enrico Arrigoni ◽  
Michael Potthoff
Keyword(s):  
Hubbard Model ◽  
Spectral Function ◽  
Single Particle ◽  
Ground State

scholarly journals Off-Diagonal Long-Range Order in Generalized Hubbard Models

1997 ◽  
Vol 11 (11) ◽  
pp. 1311-1335 ◽  
Author(s):  
Kristel Michielsen ◽  
Hans De Raedt
Keyword(s):  
Density Matrix ◽  
Hubbard Model ◽  
Long Range ◽  
Ground State ◽  
Size Dependence ◽  
State Energy ◽  
System Size ◽  
Range Order ◽  
Long Range Order ◽  
Hubbard Models

We present stochastic diagonalization results for the ground-state energy and the largest eigenvalue of the two-fermion density matrix of the BCS reduced Hamiltonian, the Hubbard model, and the Hubbard model with correlated hopping. The system-size dependence of this eigenvalue is used to study the existence of Off-Diagonal Long-Range Order in these models. We show that the model with correlated hopping and repulsive on-site interaction can exhibit Off-Diagonal Long-Range Order. Analytical results for some special limiting cases indicate that Off-Diagonal Long-Range Order not always implies superconductivity.

Phase diagram of cuprate high-temperature superconductors based on the optimization Monte Carlo method

2020 ◽  
Vol 34 (19n20) ◽  
pp. 2040046
Author(s):  
T. Yanagisawa ◽  
M. Miyazaki ◽  
K. Yamaji
Keyword(s):  
Phase Diagram ◽  
Monte Carlo ◽  
Wave Function ◽  
High Temperature ◽  
Hubbard Model ◽  
Ground State ◽  
State Energy ◽  
High Temperature Superconductivity ◽  
Two Dimensional ◽  
Text Model

It is important to understand the phase diagram of electronic states in the CuO2 plane to clarify the mechanism of high-temperature superconductivity. We investigate the ground state of electronic models with strong correlation by employing the optimization variational Monte Carlo method. We consider the two-dimensional Hubbard model as well as the three-band [Formula: see text]–[Formula: see text] model. We use the improved wave function that takes account of inter-site electron correlation to go beyond the Gutzwiller wave function. The ground state energy is lowered considerably, which now gives the best estimate of the ground state energy for the two-dimensional Hubbard model. The many-body effect plays an important role as an origin of spin correlation and superconductivity in correlated electron systems. We investigate the competition between the antiferromagnetic state and superconducting state by varying the Coulomb repulsion [Formula: see text], the band parameter [Formula: see text] and the electron density [Formula: see text] for the Hubbard model. We show phase diagrams that include superconducting and antiferromagnetic phases. We expect that high-temperature superconductivity occurs near the boundary between antiferromagnetic phase and superconducting one. Since the three-band [Formula: see text]–[Formula: see text] model contains many-band parameters, high-temperature superconductivity may be more likely to occur in the [Formula: see text]–[Formula: see text] model than in single-band models.

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