23,568 research outputs found

    Irreducible MultiQutrit Correlations in Greenberger-Horne-Zeilinger Type States

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    Following the idea of the continuity approach in [D. L. Zhou, Phys. Rev. Lett. 101, 180505 (2008)], we obtain the degrees of irreducible multi-party correlations in two families of nn-qutrit Greenberger-Horne-Zeilinger type states. For the pure states in one of the families, the irreducible 2-party, nn-party and (nm)(n-m)-party (0<m<n20< m < n-2) correlations are nonzero, which is different from the nn-qubit case. We also derive the correlation distributions in the nn-qutrit maximal slice state, which can be uniquely determined by its (n1)(n-1)-qutrit reduced density matrices among pure states. It is proved that there is no irreducible nn-qutrit correlation in the maximal slice state. This enlightens us to give a discussion about how to characterize the pure states with irreducible nn-party correlation in arbitrarily high-dimensional systems by the way of the continuity approach.Comment: 5p, no fi

    The swap operation in the two-qubit Heisenberg XXZ model-effects of anisotropy and magnetic field

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    In this paper we study the swap operation in a two-qubit anisotropic XXZ model in the presence of an inhomogeneous magnetic field. We establish the range of anisotropic parameter within which the swap operation is feasible. The swap errors caused by the inhomogeneous field are evaluated

    Computing the lower and upper bounds of Laplace eigenvalue problem: by combining conforming and nonconforming finite element methods

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    This article is devoted to computing the lower and upper bounds of the Laplace eigenvalue problem. By using the special nonconforming finite elements, i.e., enriched Crouzeix-Raviart element and extension Q1rotQ_1^{\rm rot}, we get the lower bound of the eigenvalue. Additionally, we also use conforming finite elements to do the postprocessing to get the upper bound of the eigenvalue. The postprocessing method need only to solve the corresponding source problems and a small eigenvalue problem if higher order postprocessing method is implemented. Thus, we can obtain the lower and upper bounds of the eigenvalues simultaneously by solving eigenvalue problem only once. Some numerical results are also presented to validate our theoretical analysis.Comment: 19 pages, 4 figure

    Carbon-doped ZnO: A New Class of Room Temperature Dilute Magnetic Semiconductor

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    We report magnetism in carbon doped ZnO. Our first-principles calculations based on density functional theory predicted that carbon substitution for oxygen in ZnO results in a magnetic moment of 1.78 μB\mu_B per carbon. The theoretical prediction was confirmed experimentally. C-doped ZnO films deposited by pulsed laser deposition with various carbon concentrations showed ferromagnetism with Curie temperatures higher than 400 K, and the measured magnetic moment based on the content of carbide in the films (1.53.0μB1.5 - 3.0 \mu_B per carbon) is in agreement with the theoretical prediction. The magnetism is due to bonding coupling between Zn ions and doped C atoms. Results of magneto-resistance and abnormal Hall effect show that the doped films are nn-type semiconductors with intrinsic ferromagnetism. The carbon doped ZnO could be a promising room temperature dilute magnetic semiconductor (DMS) and our work demonstrates possiblity of produing DMS with non-metal doping.Comment: REVtex source with 4 figures in eps forma

    Protective effect of Dendrobium officinale polysaccharides on experimental Sjogren's syndrome

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    Sjogren's syndrome (SS), usually described as a chronic inflammation which results in xerostomia (dry mouth) and xerophthalmia (dry eyes). According to the theory of traditional Chinese medicine, body fluid impairment causes the dryness, inducing water secretion deficiency. Discovery of a family of water-specific membrane channel proteins, the aquaporins, provides an interesting molecular mechanism of water permeability and transportation which were found abnormal in tissues of SS patients. Thus, this dryness may lead to the dysfunction in organs as various systematic manifestations. We established an autoallergic mouse model in vivo, and human salivary gland cell line A-253 in vitro. Polysaccharides of Dendrobium officinale (DP) were administrated as treatment, which was described to nourish yin and promote the body fluid. Results showed that immunization with SG autoantigen induced decrease of body weight and increased water intake, decreased AQP5 expression in a series of organs related to body fluid. Sera from model mice induced apoptosis of A-253 cells with activation of caspase-3. Administration of DP could reverse these pathological changes in both the animal and cell model. Thus, DP may be a promising candidate for the treatment of SS by up-regulating the expression of AQP-5 and protecting cells from apoptosis. © 2010 The Berkeley Electronic Press. All rights reserved.published_or_final_versio

    One-Loop Effect of Null-Like Cosmology's Holographic Dual Super-Yang-Mills

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    We calculate the 1-loop effect in super-Yang-Mills which preserves 1/4-supersymmetries and is holographically dual to the null-like cosmology with a big-bang singularity. Though the bosonic and fermionic spectra do not agree precisely, we do obtain vanishing 1-loop vacuum energy for generic warped plane-wave type backgrounds with a big-bang singularity. Moreover, we find that the cosmological "constant" contributed either by bosons or fermions is time-dependent. The issues about the particle production of some background and about the UV structure are also commented. We argue that the effective higher derivative interactions are suppressed as long as the Fourier transform of the time-dependent coupling is UV-finite. Our result holds for scalar configurations that are BPS but with arbitrary time-dependence. This suggests the existence of non-renormalization theorem for such a new class of time-dependent theories. Altogether, it implies that such a super-Yang-Mills is scale-invariant, and that its dual bulk quantum gravity might behave regularly near the big bang.Comment: 20 pages, v2 add comments and references, v3 clarify BPS condition & add new discussion on particle production and UV structure, v4&v5 minor changes, final to JHE
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