Compressibility of a two-dimensional extended Hubbard model

Compressibility of the Two-Dimensional Infinite-U Hubbard Model

We study the interactions between the coherent quasiparticles and the incoherent Mott-Hubbard excitations and their effects on the low-energy properties in the U ` Hubbard model. Within the framework of a systematic large-N expansion, these effects first occur in the next-to-leading order in 1 N . We calculate the scattering phase shift and the free energy, and determine the quasiparticle weigh...

Beyond extended dynamical mean-field theory: Dual boson approach to the two-dimensional extended Hubbard model

Dimerization in a half-filled one-dimensional extended hubbard model.

We use a density-matrix renormalization group method to study quantitatively the phase diagram of a one-dimensional extended Hubbard model at half filling by investigating the correlation functions and structure factors. We confirmed the existence of a novel narrow region with long-range bond-order-wave order that was highly controversial recently between the charge-density-wave phase and Mott ...

Superconductivity in the two-dimensional Hubbard model.

A refined variational wave function for the two-dimensional repulsive Hubbard model is studied numerically , with the aim of approaching the difficult crossover regime of intermediate values of U. The issue of a superconducting ground state with d-wave symmetry is investigated for an average electron density n ≈ 0.8 and for U = 8t. Due to finite-size effects a clear-cut answer to this fundament...

Enhanced Spin Susceptibility toward the Charge-Ordering Transition in a Two-Dimensional Extended Hubbard Model

Based on the non-skeleton diagrammatic expansion satisfying the compressibility and spinsusceptibility sum rules, we investigate static charge and spin responses in a two-dimensional extended Hubbard model with the nearest-neighbor Coulomb repulsion in the vicinity of its charge-ordering transition point. In this expansion, we can calculate approximate charge and spin response functions by syst...