9,527 research outputs found

    Transport Properties of a One-Dimensional Two-Component Quantum Liquid with Hyperbolic Interactions

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    We present an investigation of the sinh-cosh (SC) interaction model with twisted boundary conditions. We argue that, when unlike particles repel, the SC model may be usefully viewed as a Heisenberg-Ising fluid with moving Heisenberg-Ising spins. We derive the Luttinger liquid relation for the stiffness and the susceptibility, both from conformal arguments, and directly from the integral equations. Finally, we investigate the opening and closing of the ground state gaps for both SC and Heisenberg-Ising models, as the interaction strength is varied.Comment: 10 REVTeX pages + 4 uuencoded figures, UoU-002029

    A Note on Dressed S-Matrices in Models with Long-Range Interactions

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    The {\sl dressed} Scattering matrix describing scattering of quasiparticles in various models with long-range interactions is evaluated by means of Korepin's method\upref vek1/. For models with 1sin2(r){1\over\sin^2(r)}-interactions the S-matrix is found to be a momentum-independent phase, which clearly demonstrates the ideal gas character of the quasiparticles in such models. We then determine S-matrices for some models with 1sinh2(r){1\over\sinh^2(r)}-interaction and find them to be in general nontrivial. For the 1r2{1\over r^2}-limit of the 1sinh2(r){1\over\sinh^2(r)}-interaction we recover trivial S-matrices, thus exhibiting a crossover from interacting to noninteracting quasiparticles. The relation of the S-matrix to fractional statistics is discussed.Comment: 18 pages, jyTeX (macro included - just TeX the file) BONN-TH-94-13, revised version: analysis of models with 1/sinh^2 interaction adde

    The development of low temperature curing adhesives

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    An approach for the development of a practical low temperature (293 K-311 K/68 F-100 F) curing adhesive system based on a family of amide/ester resins was studied and demonstrated. The work was conducted on resin optimization and adhesive compounding studies. An improved preparative method was demonstrated which involved the reaction of an amine-alcohol precursor, in a DMF solution with acid chloride. Experimental studies indicated that an adhesive formulation containing aluminum powder provided the best performance when used in conjunction with a commercial primer

    Dynamical Mass Measurements of Contaminated Galaxy Clusters Using Machine Learning

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    We study dynamical mass measurements of galaxy clusters contaminated by interlopers and show that a modern machine learning (ML) algorithm can predict masses by better than a factor of two compared to a standard scaling relation approach. We create two mock catalogs from Multidark's publicly available NN-body MDPL1 simulation, one with perfect galaxy cluster membership information and the other where a simple cylindrical cut around the cluster center allows interlopers to contaminate the clusters. In the standard approach, we use a power-law scaling relation to infer cluster mass from galaxy line-of-sight (LOS) velocity dispersion. Assuming perfect membership knowledge, this unrealistic case produces a wide fractional mass error distribution, with a width of Δϵ0.87\Delta\epsilon\approx0.87. Interlopers introduce additional scatter, significantly widening the error distribution further (Δϵ2.13\Delta\epsilon\approx2.13). We employ the support distribution machine (SDM) class of algorithms to learn from distributions of data to predict single values. Applied to distributions of galaxy observables such as LOS velocity and projected distance from the cluster center, SDM yields better than a factor-of-two improvement (Δϵ0.67\Delta\epsilon\approx0.67) for the contaminated case. Remarkably, SDM applied to contaminated clusters is better able to recover masses than even the scaling relation approach applied to uncontaminated clusters. We show that the SDM method more accurately reproduces the cluster mass function, making it a valuable tool for employing cluster observations to evaluate cosmological models.Comment: 18 pages, 12 figures, accepted for publication at Ap

    Exact calculation of the ground-state dynamical spin correlation function of a S=1/2 antiferromagnetic Heisenberg chain with free spinons

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    We calculate the exact dynamical magnetic structure factor S(Q,E) in the ground state of a one-dimensional S=1/2 antiferromagnet with gapless free S=1/2 spinon excitations, the Haldane-Shastry model with inverse-square exchange, which is in the same low-energy universality class as Bethe's nearest-neighbor exchange model. Only two-spinon excited states contribute, and S(Q,E) is found to be a very simple integral over these states.Comment: 11 pages, LaTeX, RevTeX 3.0, cond-mat/930903

    A study of the composition of some eye cosmetics (kohls) used in the United Arab Emirates

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    A total of 23 kohl samples was analyzed using X-ray powder diffraction (XRPD) and scanning electron microscopy (SEM). Nineteen samples were obtained in Abu Dhabi and four in Dubai. None of the samples were made in the United Arab Emirates. The main component of 11 samples was found to be galena (PbS). For the remaining 12 samples, the main component was found to be one of the following: amorphous carbon, zincite (ZnO), sassolite (H3BO3) or calcite/aragonite (CaCO3). © 2002 Elsevier Science Ireland Ltd. All rights reserved

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

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    We present the exact solution of two Heisenberg-liquid models of particles with arbitrary spin SS 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

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

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    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
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