Using the method introduced by Grisaru et al., boundary S matrices for the physical excitations of the open Hubbard chain with boundary fields are studied. In contrast to the open supersymmetric t-J model, the boundary S matrix for the charge excitations depend on the boundary fields though the boundary fields do not break the spin-SU(2) symmetry. E-mail address: [email protected]

The zero-temperature transition from a paramagnetic metal to a paramagnetic insulator is investigated in the dynamical mean field theory for the Hubbard model. The self-energy of the effective impurity Anderson model (on which the Hubbard model is mapped) is calculated using Wilson’s numerical renormalization group method. Results for the quasiparticle weight, the spectral function, and the sel...

We propose a general framework that leads to one-dimensional XX and Hubbard models in full generality, based on the decomposition of an arbitrary vector space (possibly infinite dimensional) into a direct sum of two subspaces, the two corresponding orthogonal projectors allowing one to define a R-matrix of a universal XX model, and then of a Hubbard model using a Shastry type construction. The ...

The Hubbard model with an additional bond-charge interaction X is solved exactly in one dimension for the case t = X where t is the hopping amplitude. In this case the number of doubly occupied sites is conserved. In the sector with no double occupations the model reduces to the U = ∞ Hubbard model. In arbitrary dimensions the qualitative form of the phase diagram is obtained. It is shown that ...

Charged excitons in doped extended Hubbard model systems. Abstract We show that the charge transfer excitons in a Hubbard model system including nearest neighbor Coulomb interactions effectively attain some charge in doped systems and become visible in photoelectron and inverse photoelec-tron spectroscopies. This shows that the description of a doped system by an extended Hubbard model differs ...

A momentum-space approach of the density-matrix renormalization-group ~DMRG! method is developed. Ground-state energies of the Hubbard model are evaluated using this method and compared with exact diagonalization as well as quantum Monte Carlo results. It is shown that the momentum-space DMRG is a very useful numerical tool for studying the Hubbard model and other fundamental models of interact...

We show that the critical point of the two-dimensional Bose-Hubbard model can be easily found through studies of either on-site atom number fluctuations or the nearest-neighbor two-point correlation function (the expectation value of the tunnelling operator). Our strategy to locate the critical point is based on the observation that the derivatives of these observables with respect to the param...

The Hubbard model, a lattice model for spin 1/2 fermions with nearest neighbor “hopping”and an on-site repulsion, plays a special role in condensed matter physics. It is the simplest theoretical model describing correlated electronic systems. Originally introduced to describe the effects of screened Coulomb interaction in narrow band materials, the Hubbard model defined on square lattice gains ...