550 research outputs found

    Hund's Rule for Composite Fermions

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    We consider the ``fractional quantum Hall atom" in the vanishing Zeeman energy limit, and investigate the validity of Hund's maximum-spin rule for interacting electrons in various Landau levels. While it is not valid for {\em electrons} in the lowest Landau level, there are regions of filling factors where it predicts the ground state spin correctly {\em provided it is applied to composite fermions}. The composite fermion theory also reveals a ``self-similar" structure in the filling factor range 4/3>ν>2/34/3>\nu>2/3.Comment: 10 pages, revte

    Fractional Quantum Hall States in Low-Zeeman-Energy Limit

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    We investigate the spectrum of interacting electrons at arbitrary filling factors in the limit of vanishing Zeeman splitting. The composite fermion theory successfully explains the low-energy spectrum {\em provided the composite fermions are treated as hard-core}.Comment: 12 pages, revte

    Novel Correspondence-based Approach for Consistent Human Skeleton Extraction

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    This paper presents a novel base-points-driven shape correspondence (BSC) approach to extract skeletons of articulated objects from 3D mesh shapes. The skeleton extraction based on BSC approach is more accurate than the traditional direct skeleton extraction methods. Since 3D shapes provide more geometric information, BSC offers the consistent information between the source shape and the target shapes. In this paper, we first extract the skeleton from a template shape such as the source shape automatically. Then, the skeletons of the target shapes of different poses are generated based on the correspondence relationship with source shape. The accuracy of the proposed method is demonstrated by presenting a comprehensive performance evaluation on multiple benchmark datasets. The results of the proposed approach can be applied to various applications such as skeleton-driven animation, shape segmentation and human motion analysis

    Skyrmion Excitations in Quantum Hall Systems

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    Using finite size calculations on the surface of a sphere we study the topological (skyrmion) excitation in quantum Hall system with spin degree of freedom at filling factors around ν=1\nu=1. In the absence of Zeeman energy, we find, in systems with one quasi-particle or one quasi-hole, the lowest energy band consists of states with L=SL=S, where LL and SS are the total orbital and spin angular momentum. These different spin states are almost degenerate in the thermodynamic limit and their symmetry-breaking ground state is the state with one skyrmion of infinite size. In the presence of Zeeman energy, the skyrmion size is determined by the interplay of the Zeeman energy and electron-electron interaction and the skyrmion shrinks to a spin texture of finite size. We have calculated the energy gap of the system at infinite wave vector limit as a function of the Zeeman energy and find there are kinks in the energy gap associated with the shrinking of the size of the skyrmion. breaking ground state is the state with one skyrmion of infinite size. In the presence of Zeeman energy, the skyrmion size is determined by the interplay of the Zeeman energy and electron-electronComment: 4 pages, 5 postscript figures available upon reques

    Separable Subsurface Scattering

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    In this paper, we propose two real-time models for simulating subsurface scattering for a large variety of translucent materials, which need under 0.5 ms per frame to execute. This makes them a practical option for real-time production scenarios. Current state-of-the-art, real-time approaches simulate subsurface light transport by approximating the radially symmetric non-separable diffusion kernel with a sum of separable Gaussians, which requires multiple (up to 12) 1D convolutions. In this work we relax the requirement of radial symmetry to approximate a 2D diffuse reflectance profile by a single separable kernel. We first show that low-rank approximations based on matrix factorization outperform previous approaches, but they still need several passes to get good results. To solve this, we present two different separable models: the first one yields a high-quality diffusion simulation, while the second one offers an attractive trade-off between physical accuracy and artistic control. Both allow rendering of subsurface scattering using only two 1D convolutions, reducing both execution time and memory consumption, while delivering results comparable to techniques with higher cost. Using our importance-sampling and jittering strategies, only seven samples per pixel are required. Our methods can be implemented as simple post-processing steps without intrusive changes to existing rendering pipelines

    Exclusion Statistics of Quasiparticles in Condensed States of Composite Fermion Excitations

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    The exclusion statistics of quasiparticles is found at any level of the hierarchy of condensed states of composite fermion excitations (for which experimental indications have recently been found). The hierarchy of condensed states of excitations in boson Jain states is introduced and the statistics of quasiparticles is found. The quantum Hall states of charged α\alpha-anyons (α\alpha -- the exclusion statistics parameter) can be described as incompressible states of (α+2p)(\alpha+2p)-anyons (2p2p -- an even number).Comment: 4 page

    Development and Characterization of Neutralizing Antibodies Against Zaire Ebolavirus Glycoprotein and Protein 40

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    Background/Aims: Monoclonal antibodies (mAbs) are presently the most promising treatment against Ebola virus disease (EVD), and cocktail of two or more antibodies likely confers protection through complementary mechanisms. Zaire Ebolavirus (EBOV) glycoprotein (GP) and viral protein 40 (VP40) are targets for designing neutralizing antibodies. Currently, the antiviral therapeutics of mAb-cocktails are still limited solely to anti-GP antibodies,there is no Abs cocktail against Zaire EBOV GP and VP40, which both have important interactions with host cellular membrane. Methods: We used hybridoma technology to produce anti-Zaire EBOV GP mAb against GP receptor binding domain, and anti-Zaire EBOV VP40 mAbs against the N-terminal domain, the C-terminal domain, respectively; synthesized Zaire EBOV transcription and replication competent virus like particles (trVLPs), which model even all aspects of the EBOV life cycles in order to evaluate the anti-viral effect of mAbs. Then, we characterized the anti- Zaire EBOV trVLPs effect of anti-GP and VP40 mAbs in vitro by real time-PCR, immunofluorescence assay and western blot analysis. Results: Our results demonstrate that anti-GP or anti-VP40 mAbs effectively inhibit trVLPs replication. The cocktails of anti-GP and anti-VP40 mAbs, or between anti-VP40 mAbs, had synergistic anti-trVLPs effect. Meanwhile, the detailed DNA and amino acid sequences of the mAbs were checked. Conclusion: The study verifies neutralizing efficacy of anti-GP or anti-VP40 mAb, report promising cocktail of anti-GP and anti-VP40 mAb, or cocktail of two anti-VP40 mAbs. To our knowledge, this is the first account to report the important anti-viral effect of cocktails of anti-GP and anti-VP40 mAbs in vitro

    Striped antiferromagnetic order and electronic properties of stoichiometric LiFeAs from first-principles calculations

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    We investigate the structural, electronic, and magnetic properties of stoichiometric LiFeAs by using state-of-the-arts first-principles method. We find the magnetic ground-state by comparing the total energies among all the possible magnetic orders. Our calculated internal positions of Li and As are in good agreement with experiment. Our results show that stoichiometric LiFeAs has almost the same striped antiferromagnetic spin order as other FeAs-based parent compounds and tetragonal FeSe do, and the experimental fact that no magnetic phase transition has been observed at finite temperature is attributed to the tiny inter-layer spin coupling

    Composite Fermion Description of Correlated Electrons in Quantum Dots: Low Zeeman Energy Limit

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    We study the applicability of composite fermion theory to electrons in two-dimensional parabolically-confined quantum dots in a strong perpendicular magnetic field in the limit of low Zeeman energy. The non-interacting composite fermion spectrum correctly specifies the primary features of this system. Additional features are relatively small, indicating that the residual interaction between the composite fermions is weak. \footnote{Published in Phys. Rev. B {\bf 52}, 2798 (1995).}Comment: 15 pages, 7 postscript figure

    Energy, interaction, and photoluminescence of spin-reversed quasielectrons in fractional quantum Hall systems

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    The energy and photoluminescence spectra of a two-dimensional electron gas in the fractional quantum Hall regime are studied. The single-particle properties of reversed-spin quasielectrons (QER_{\rm R}'s) as well as the pseudopotentials of their interaction with one another and with Laughlin quasielectrons (QE's) and quasiholes (QH's) are calculated. Based on the short-range character of the QER_{\rm R}--QER_{\rm R} and QER_{\rm R}--QE repulsion, the partially unpolarized incompressible states at the filling factors ν=411\nu={4\over11} and 513{5\over13} are postulated within Haldane's hierarchy scheme. To describe photoluminescence, the family of bound h(h(QER)n_{\rm R})_n states of a valence hole hh and nn QER_{\rm R}'s are predicted in analogy to the found earlier fractionally charged excitons hhQEn_n. The binding energy and optical selection rules for both families are compared. The hhQER_{\rm R} is found radiative in contrast to the dark hhQE, and the h(h(QER)2_{\rm R})_2 is found non-radiative in contrast to the bright hhQE2_2.Comment: 9 pages, 6 figure
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