Solutions to the Multi-Component 1/R Hubbard Model

In this work we introduce one dimensional multi-component Hubbard model of 1/r hopping and U on-site energy. The wavefunctions, the spectrum and the thermodynamics are studied for this model in the strong interaction limit $U=\infty$. In this limit, the system is a special example of $SU(N)$ Luttinger liquids, exhibiting spin-charge separation in the full Hilbert space. Speculations on the physical properties of the model at finite on-site energy are also discussed.Comment: 9 pages, revtex, Princeton-May1

Solution of Some Integrable One-Dimensional Quantum Systems

In this paper, we investigate a family of one-dimensional multi-component quantum many-body systems. The interaction is an exchange interaction based on the familiar family of integrable systems which includes the inverse square potential. We show these systems to be integrable, and exploit this integrability to completely determine the spectrum including degeneracy, and thus the thermodynamics. The periodic inverse square case is worked out explicitly. Next, we show that in the limit of strong interaction the "spin" degrees of freedom decouple. Taking this limit for our example, we obtain a complete solution to a lattice system introduced recently by Shastry, and Haldane; our solution reproduces the numerical results. Finally, we emphasize the simple explanation for the high multiplicities found in this model

Partially Solvable Anisotropic t-J Model with Long-Range Interactions

A new anisotropic t-J model in one dimension is proposed which has long-range hopping and exchange. This t-J model is only partially solvable in contrast to known integrable models with long-range interaction. In the high-density limit the model reduces to the XXZ chain with the long-range exchange. Some exact eigenfunctions are shown to be of Jastrow-type if certain conditions for an anisotropy parameter are satisfied. The ground state as well as the excitation spectrum for various cases of the anisotropy parameter and filling are derived numerically. It is found that the Jastrow-type wave function is an excellent trial function for any value of the anisotropy parameter.Comment: 10 pages, 3 Postscript figure

Spectral flow in the supersymmetric tt-JJ model with a 1/r21/r^2 interaction

The spectral flow in the supersymmetric {\it t-J} model with $1/r^2$ interaction is studied by analyzing the exact spectrum with twisted boundary conditions. The spectral flows for the charge and spin sectors are shown to nicely fit in with the motif picture in the asymptotic Bethe ansatz. Although fractional exclusion statistics for the spin sector clearly shows up in the period of the spectral flow at half filling, such a property is generally hidden once any number of holes are doped, because the commensurability condition in the motif is not met in the metallic phase.Comment: 8 pages, revtex, Phys. Rev. B54 (1996) August 15, in pres

Exact Solution of Heisenberg-liquid models with long-range coupling

We present the exact solution of two Heisenberg-liquid models of particles with arbitrary spin $S$ interacting via a hyperbolic long-range potential. In one model the spin-spin coupling has the simple antiferromagnetic Heisenberg exchange form, while for the other model the interaction is of the ferromagnetic Babujian-Takhatajan type. It is found that the Bethe ansatz equations of these models have a similar structure to that of the Babujian-Takhatajan spin chain. We also conjecture the integrability of a third new spin-lattice model with long-range interaction.Comment: 7pages Revte

\u27Dermo\u27 fleece rot and body strike on sheep

Blowfly strike is one of the major problems confronting the sheep industry in Austrsalia, with an estimated totsalcost of control eceeding $100 million each year. Sheep are susceptible to five types of strike: body, breach, poll, pizzle and wound. Body strike, is of greater economic importance because its sporadic occurence from year to year makes it difficult to predict and cintrol. Outbreaks of body strike after rain can affect large numbers of sheep and inflict severe production losses. In eastern Australia fleece rot is generally considered to be the main predisposing factor to blowfly strike, but in Western Australia evidence suggests that dermatophilosis - or \u27dermo\u27 - is the more important factor

Exact Results of the 1D 1/r21/r^2 Supersymmetric t-J Model without Translational Invariance

In this work, we continue the study of the supersymmetric t-J model with 1/r^2 hopping and exchange without translational invariance. A set of Jastrow wavefunctions are obtained for the system, with eigenenergies explicitly calculated. The ground state of the t-J model is included in this set of wavefunctions. The spectrum of this t-J model consists of equal-distant energy levels which are highly degenerate.Comment: 14 pages, Late

Conservation status of New Zealand freshwater invertebrates, 2013

The conservation status of 644 freshwater invertebrate taxa, across five Phyla, 28 Orders and 75 Families, was assessed using the New Zealand Threat Classification System (NZTCS) criteria. Forty-six species were ranked Nationally Critical, 11 Nationally Endangered and 16 Nationally Vulnerable. One hundred and seventy-two taxa were listed as Data Deficient. A full list is presented, along with summaries and brief notes on the most important changes. This list replaces all previous NZTCS lists for freshwater invertebrates

Invariants of the Haldane-Shastry SU(N)SU(N) Chain

Using a formalism developed by Polychronakos, we explicitly construct a set of invariants of the motion for the Haldane-Shastry $SU(N)$ chain.Comment: 11 pages, UVA-92-0

Long Range Interaction Models and Yangian Symmetry

The generalized Sutherland-Romer models and Yan models with internal spin degrees are formulated in terms of the Polychronakos' approach and RTT relation associated to the Yang-Baxter equation in consistent way. The Yangian symmetry is shown to generate both models. We finally introduce the reflection algebra K(u) to the long range models.Comment: 13 pages, preprint of Nankai Institute of Mathematics ( Theoretical Physics Division ), published in Physical Review E of 1995. For hard copy, write to Prof. Mo-lin GE directly. Do not send emails to this accoun