Testing the Monte Carlo–mean field approximation in the one-band Hubbard model

Variational Monte Carlo study of the two-band Hubbard model

Magnetic Properties of the One-Band Hubbard Model

The microscopic description of magnetism to this day constitutes one of the major areas of research in modern solid state theory. Motivated by a wide variety of interesting phenomena, the development of new methods for an accurate description of these materials is one of the most exciting fields of physics. This is true in particular for materials where the interactions between the electrons pl...

Quantum Monte Carlo evidence for superconductivity in the three-band hubbard Model in Two Dimensions.

A possibility of the electronic origin of the high-temperature superconductivity in cuprates is probed with the quantum Monte Carlo method by revisiting the three-band Hubbard model comprising Cu3dx2−y2 and O2pσ orbitals. The dx2−y2 pairing correlation is found to turn into an increasing function of the repulsion Ud within the d orbitals or the d-p level off-set ∆ε, where the correlation grows ...

Gutzwiller wave function in the three-band Hubbard model: A variational Monte Carlo study.

The Gutzwiller wave function for the three-band Hubbard model on a two dimensional CuO2 plane is studied by using the variational Monte Carlo (VMC) method in the limit Ud → ∞, where Ud is the Coulomb repulsion between holes on a Cu site. The VMC results for the energy and the fraction of d-holes are compared with those of the Rice-Ueda type Gutzwiller approximation (GA). The difference between ...

Random Dispersion Approximation for the Hubbard model

We use the Random Dispersion Approximation (RDA) to study the Mott-Hubbard transition in the Hubbard model at half band filling. The RDA becomes exact for the Hubbard model in infinite dimensions. We implement the RDA on finite chains and employ the Lanczos exact diagonalization method in real space to calculate the ground-state energy, the average double occupancy, the charge gap, the momentum...