Integrable boundary impurities in the t-J model with different gradings

We investigate the generalized supersymmetric $t-J$ model with boundary impurities in different gradings. All three different gradings: fermion, fermion, boson (FFB), boson, fermion, fermion (BFF) and fermion, boson, fermion (FBF), are studied for the generalized supersymmetric $t-J$ model. Boundary K-matrix operators are found for the different gradings. By using the graded algebraic Bethe ansatz method, we obtain the eigenvalues and the corresponding Bethe ansatz equations for the transfer matrix.Comment: Latex file, 20 page

Open t-J chain with boundary impurities

We study integrable boundary conditions for the supersymmetric t-J model of correlated electrons which arise when combining static scattering potentials with dynamical impurities carrying an internal degree of freedom. The latter differ from the bulk sites by allowing for double occupation of the local orbitals. The spectrum of the resulting Hamiltonians is obtained by means of the algebraic Bethe Ansatz.Comment: LaTeX2e, 9p

Jordan-Wigner fermionization for the one-dimensional Bariev model of three coupled XY chains

The Jordan-Wigner fermionization for the one-dimensional Bariev model of three coupled XY chains is formulated. The Lax operator in terms of fermion operators and the quantum R-matrix are presented explicitly. Furthermore, the graded reflection equations and their solutions are discussed.Comment: 10 pages, no figur

Pair correlation functions in one-dimensional correlated-hopping models

We investigate ground-state properties of two correlated-hopping electron models, the Hirsch and the Bariev model. Both models are of recent interest in the context of hole superconductivity. Applying the Lanczos technique to small clusters, we numerically determine the binding energy, the spin gaps, correlation functions, and other properties for various values of the bond-charge interaction parameter. Our results for small systems indicate that pairing is favoured in a certain parameter range. However, in contrast to the Bariev model, superconducting correlations are suppressed in the Hirsch model, for a bond-charge repulsion larger than a critical value.Comment: 7 pages (LaTeX) + 6 postcript figures in a separate uuencoded fil

Integrable open boundary conditions for the Bariev model of three coupled XY spin chains

The integrable open-boundary conditions for the Bariev model of three coupled one-dimensional XY spin chains are studied in the framework of the boundary quantum inverse scattering method. Three kinds of diagonal boundary K-matrices leading to nine classes of possible choices of boundary fields are found and the corresponding integrable boundary terms are presented explicitly. The boundary Hamiltonian is solved by using the coordinate Bethe ansatz technique and the Bethe ansatz equations are derived.Comment: 21 pages, no figure

Friedel oscillations in one-dimensional metals: from Luttinger's theorem to the Luttinger liquid

Charge density and magnetization density profiles of one-dimensional metals are investigated by two complementary many-body methods: numerically exact (Lanczos) diagonalization, and the Bethe-Ansatz local-density approximation with and without a simple self-interaction correction. Depending on the magnetization of the system, local approximations reproduce different Fourier components of the exact Friedel oscillations.Comment: 3 pages, 3 figures, Manuscript accepted by Journal of Magnetism and Magnetic Materials, special issue for LAWMMM 2007 conferenc

Algebraic properties of an integrable t-J model with impurities

We investigate the algebraic structure of a recently proposed integrable $t-J$ model with impurities. Three forms of the Bethe ansatz equations are presented corresponding to the three choices for the grading. We prove that the Bethe ansatz states are highest weight vectors of the underlying $gl(2|1)$ supersymmetry algebra. By acting with the $gl(2|1)$ generators we construct a complete set of states for the model.Comment: 20 pages, LaTe

Comment on “Model of Fermions with Correlated Hopping (Integrable Cases)”

A Comment of the Letter by Igor N. Karnaukhov Phys. Rev. Lett. 73, 1130 (94). The authors of the Letter offer a Reply

Integrable variant of the one-dimensional Hubbard model

A new integrable model which is a variant of the one-dimensional Hubbard model is proposed. The integrability of the model is verified by presenting the associated quantum R-matrix which satisfies the Yang-Baxter equation. We argue that the new model possesses the SO(4) algebra symmetry, which contains a representation of the $\eta$-pairing SU(2) algebra and a spin SU(2) algebra. Additionally, the algebraic Bethe ansatz is studied by means of the quantum inverse scattering method. The spectrum of the Hamiltonian, eigenvectors, as well as the Bethe ansatz equations, are discussed

Dual-Path Mechanism for Catalytic Oxidation of Hydrogen on Platinum Surfaces

The catalytic formation of water from adsorbed hydrogen and oxygen atoms on Pt(111) was studied with scanning tunneling microscopy and high resolution electron energy loss spectroscopy. The known complexity of this reaction is explained by the strongly temperature dependent lifetime of the product H2O molecules on the surface. Below the desorption temperature water reacts with unreacted O adatoms to OHad, leading to an autocatalytic process; at higher temperatures sequential addition of H adatoms to Oad with normal kinetics takes place