4,799 research outputs found

    Solitons in Chern-Simons theories of nonrelativistic CP^{N-1} models: Spin textures in the quantum Hall effect

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    Topological solitons in CP^{N-1} models coupled with Chern-Simons gauge theory and a Hopf term are studied both analytically and numerically.These models are low-energy effective theories for the quantum Hall effect with internal degrees of freedom, like that in bilayer electron systems. We explicitly show that the CP^{N-1} models describe quite well spin textures in the original Chern-Simons theory of bosonized electrons.Comment: Latex, 19 pages, 6 figure

    Spin dependent recombination based magnetic resonance spectroscopy of bismuth donor spins in silicon at low magnetic fields

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    Low-field (6-110 mT) magnetic resonance of bismuth (Bi) donors in silicon has been observed by monitoring the change in photoconductivity induced by spin dependent recombination. The spectra at various resonance frequencies show signal intensity distributions drastically different from that observed in conventional electron paramagnetic resonance, attributed to different recombination rates for the forty possible combinations of spin states of a pair of a Bi donor and a paramagnetic recombination center. An excellent tunability of Bi excitation energy for the future coupling with superconducting flux qubits at low fields has been demonstrated.Comment: 5 pages, 4 figure

    Decision Procedure for Entailment of Symbolic Heaps with Arrays

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    This paper gives a decision procedure for the validity of en- tailment of symbolic heaps in separation logic with Presburger arithmetic and arrays. The correctness of the decision procedure is proved under the condition that sizes of arrays in the succedent are not existentially bound. This condition is independent of the condition proposed by the CADE-2017 paper by Brotherston et al, namely, one of them does not imply the other. For improving efficiency of the decision procedure, some techniques are also presented. The main idea of the decision procedure is a novel translation of an entailment of symbolic heaps into a formula in Presburger arithmetic, and to combine it with an external SMT solver. This paper also gives experimental results by an implementation, which shows that the decision procedure works efficiently enough to use

    Anti de Sitter Holography via Sekiguchi Decomposition

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    In the present paper we start consideration of anti de Sitter holography in the general case of the (q+1)-dimensional anti de Sitter bulk with boundary q-dimensional Minkowski space-time. We present the group-theoretic foundations that are necessary in our approach. Comparing what is done for q=3 the new element in the present paper is the presentation of the bulk space as the homogeneous space G/H = SO(q,2)/SO(q,1), which homogeneous space was studied by Sekiguchi.Comment: 10 pages, to appear in the Proceedings of the XI International Workshop "Lie Theory and Its Applications in Physics", (Varna, Bulgaria, June 2015

    Classical Coulomb three-body problem in collinear eZe configuration

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    Classical dynamics of two-electron atom and ions H^{-}, He, Li+^{+}, Be2+^{2+},... in collinear eZe configuration is investigated. It is revealed that the mass ratio ξ\xi between necleus and electron plays an important role for dynamical behaviour of these systems. With the aid of analytical tool and numeircal computation, it is shown that thanks to large mass ratio ξ\xi, classical dynamics of these systems is fully chaotic, probably hyperbolic. Experimental manifestation of this finding is also proposed.Comment: Largely rewritten. 21 pages. All figures are available in http://ace.phys.h.kyoto-u.ac.jp/~sano/3-body/index.htm

    The Cut & Enhance method : selecting clusters of galaxies from the SDSS commissioning data

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    We describe an automated method, the Cut & Enhance method (CE) for detecting clusters of galaxies in multi-color optical imaging surveys. This method uses simple color cuts, combined with a density enhancement algorithm, to up-weight pairs of galaxies that are close in both angular separation and color. The method is semi-parametric since it uses minimal assumptions about cluster properties in order to minimize possible biases. No assumptions are made about the shape of clusters, their radial profile or their luminosity function. The method is successful in finding systems ranging from poor to rich clusters of galaxies, of both regular and irregular shape. We determine the selection function of the CE method via extensive Monte Carlo simulations which use both the real, observed background of galaxies and a randomized background of galaxies. We use position shuffled and color shuffled data to perform the false positive test. We have also visually checked all the clusters detected by the CE method. We apply the CE method to the 350 deg^2 of the SDSS (Sloan Digital Sky Survey) commissioning data and construct a SDSS CE galaxy cluster catalog with an estimated redshift and richness for each cluster. The CE method is compared with other cluster selection methods used on SDSS data such as the Matched Filter (Postman et al. 1996, Kim et al. 2001), maxBCG technique (Annis et al. 2001) and Voronoi Tessellation (Kim et al. 2001). The CE method can be adopted for cluster selection in any multi-color imaging surveys.Comment: 62 pages, 32 figures, Accepted for publication in the Astronomical Journal, "the CE galaxy cluster catalog can be downloaded from, http://astrophysics.phys.cmu.edu/~tomo/ce/

    Hyperfine clock transitions of bismuth donors in silicon detected by spin-dependent recombination

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    Bismuth donors ion-implanted in 28Si and natSi are studied using magnetic resonance spectroscopy based on spin-dependent recombination. The hyperfine clock transition, at which the linewidth is significantly narrowed, is observed for the bismuth donors. The experimental results are modeled quantitatively by molecular orbital theory for a coupled pair consisting of a bismuth donor and a spin-dependent recombination readout center, including the effect of hyperfine and Zeeman interactions

    Mild Dehydration Led to Increased Difficulty Falling Asleep

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    Sleep is fundamental process that benefits health and overall quality of life which can be affected by various aspects of daily living such as dehydration. A study has yet to investigate the impacts of euhydration and mild dehydration on sleep. PURPOSE: The purpose of this study was to examine effects of euhydration, mild-dehydration, and ad libitum drinking on sleep. METHODS: Eighteen male participants (mean±SD; age, 23±4y; height, 175.8±5.7cm; weight, 80.1±9.7kg) reported to the laboratory with different hydration status for 4 consecutive mornings(Day 1, baseline; Day 2, euhydrated; Day 3, mild-dehydrated; Day 4, ad libitum drinking). Hydration status was monitored by first morning urine specific gravity (USG) and plasma osmolality. Sleepwas measured using the Karolinska sleep diary (KSD). RESULTS: USG (baseline, 1.024±0.006; euhydrated, 1.018±0.007; mild-dehydrated, 1.030±0.003; ad libitum, 1.021±0.008, pCONCLUSION: When subjects were mildly dehydrated, sleep duration was longer while it was more difficult to fall asleep. More research is necessary, but the results of this study suggest it may be important to maintain euhydration to fall asleep easier
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