Crossover from weakly to strongly correlated regions in the two-dimensional Hubbard model -- Off-diagonal wave function Monte Carlo studies of Hubbard model II --

Abstract

The ground state of the two-dimensional (2D) Hubbard model is investigated by adopting improved wave functions that take into account intersite electron correlation beyond the Gutzwiller ansatz. The ground-state energy is lowered considerably, giving the best estimate of the ground-state energy for the 2D Hubbard model. There is a crossover from weakly to strongly correlated regions as the on-site Coulomb interaction $U$ increases. The antiferromagnetic correlation induced by $U$ is reduced for hole doping when $U$ is large, being greater than the bandwidth, thus increasing the kinetic energy gain. The spin and charge fluctuations are induced in the strongly correlated region. These antiferromagnetic and kinetic charge fluctuations induce electron pairings, which would result in high-temperature superconductivity.

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Cited by in corpus (7)

• Mechanism of High-Temperature Superconductivity in Correlated-Electron Systems
• Hybrid Auxiliary Field Quantum Monte Carlo for Molecular Systems
• Antiferromagnetism, Superconductivity and Phase Diagram in the Two-Dimensional Hubbard Model -- Off-Diagonal Wave Function Monte Carlo Studies of Hubbard Model III --
• Nambu-Goldstone bosons characterized by the order parameter in spontaneous symmetry breaking
• Enhancement of superconductivity due to kinetic-energy effect in the strongly correlated phase of the two-dimensional Hubbard model
• Isotope shift of the ferromagnetic transition temperature in itinerant ferromagnets
• Superconductivity and inhomogeneous charge-ordered state in the two-Dimensional Hubbard model -- Off-Diagonal Wave Function Monte Carlo Studies of Hubbard Model IV