6 research outputs found
Integro-Difference Equation for a correlation function of the spin- Heisenberg XXZ chain
We consider the Ferromagnetic-String-Formation-Probability correlation
function (FSFP) for the spin- Heisenberg XXZ chain. We construct a
completely integrable system of integro-difference equations (IDE), which has
the FSFP as a -function. We derive the associated Riemann-Hilbert problem
and obtain the large distance asymptotics of the FSFP correlator in some
limiting cases.Comment: 14 pages, latex+epsf, 1 figur
SU(2)xSU(2) Invariant Scattering Matrix of the Hubbard Model
We consider the one-dimensional half-filled Hubbard model. We show that the
excitation spectrum is given by the scattering states of four elementary
excitations, which form the fundamental representation of .
We determine the exact two-particle Scattering matrix, which a solution of the
Yang-Baxter equation and reflects the symmetry of the model. The
results for repulsive and attractive Hubbard model are related by an
interchange of spin and charge degrees of freedom.Comment: 29 pages, jyTeX (macro included - just TeX the file) ITP-SB-93-45,
BONN-HE-93-3
Faceting Transition in an Exactly Solvable Terrace-Ledge-Kink model
We solve exactly a Terrace-Ledge-Kink (TLK) model describing a crystal
surface at a microscopic level. We show that there is a faceting transition
driven either by temperature or by the chemical potential that controls the
slope of the surface. In the rough phase we investigate thermal fluctuations of
the surface using Conformal Field Theory.Comment: 27 pages, 18 EPS figure
Charge-density waves in one-dimensional Hubbard superlattices
We study the formation of charge density waves (CDW's) in one-dimensional
Hubbard superlattices, modeled by a repeated pattern of repulsive (U>0) and
free (U=0) sites. By means of Lanczos diagonalizations for the ground state, we
calculate the charge structure factor. Our results show that while the
superlattice structure affects the modulation of the charge density waves, the
periodicity can still be predicted through an effective density. We also show
that, for a fixed repulsive layer thickness, the periodicity of the CDW is an
oscillatory function of the free layer thickness.Comment: 4 pages, 4 figure
Integro-Difference Equation for a correlation function of the spin-½ Heisenberg XXZ chain
We consider the Ferromagnetic-String-Formation-Probability correlation function (FSFP) for the spin-½ Heisenberg XXZ chain. We construct a completely integrable system of integro-difference equations (IDE), which has the FSFP as a ø-function. We derive the associated Riemann-Hilbert problem and obtain the large distance asymptotics of the FSFP correlator in some limiting cases