4,272 research outputs found

    A fresh look on the flux tube in Abelian-projected SU(2) gluodynamics

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    We reconsider the properties of the QQˉQ\bar{Q} flux tube within Abelian-projected SU(2) lattice gauge theory in terms of electric field and monopole current. In the maximal Abelian gauge we assess the influence of the Gribov copies on the apparent flux-tube profile. For the optimal gauge fixing we study the independence of the profile on the lattice spacing for ÎČ=\beta= 2.3, 2.4, and 2.5115 on a 32432^4 lattice. We decompose the Abelian Wilson loop into monopole and photon parts and compare the electric and monopole profile emerging from different sources with the field strength and monopole current within the dual Ginzburg-Landau theory.Comment: 3 pages, 6 figures, Lattice2002(topology

    Spin-Glass and Chiral-Glass Transitions in a ±J\pm J Heisenberg Spin-Glass Model in Three Dimensions

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    The three-dimensional ±J\pm J Heisenberg spin-glass model is investigated by the non-equilibrium relaxation method from the paramagnetic state. Finite-size effects in the non-equilibrium relaxation are analyzed, and the relaxation functions of the spin-glass susceptibility and the chiral-glass susceptibility in the infinite-size system are obtained. The finite-time scaling analysis gives the spin-glass transition at Tsg/J=0.21−0.02+0.01T_{\rm sg}/J=0.21_{-0.02}^{+0.01} and the chiral-glass transition at Tcg/J=0.22−0.03+0.01T_{\rm cg}/J=0.22_{-0.03}^{+0.01}. The results suggest that both transitions occur simultaneously. The critical exponent of the spin-glass susceptibility is estimated as Îłsg=1.7±0.3\gamma_{\rm sg}= 1.7 \pm 0.3, which makes an agreement with the experiments of the insulating and the canonical spin-glass materials.Comment: 4 pages, 2 figure

    Redshift-space Distortions of the Power Spectrum of Cosmological Objects on a Light Cone : Explicit Formulations and Theoretical Implications

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    We examine the effects of the linear and the cosmological redshift-space distortions on the power spectrum of cosmological objects on a light cone. We develop theoretical formulae for the power spectrum in linear theory of density perturbations in a rigorous manner starting from first principle corresponding to Fourier analysis. Approximate formulae, which are useful properly to incorporate the redshift-space distortion effects into the power spectrum are derived, and the validity is examined. Applying our formulae to galaxy and quasar samples which roughly match the SDSS survey, we will show how the redshift-space distortions distort the power spectrum on the light cone quantitatively.Comment: 30 pages, Accepted for publication in the Astrophysical Journal Supplement Serie

    Structural Study of an Amorphous Bi-Fe-Ca-O Thin Film by the Anomalous X-ray Scattering

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    The structure of the amorphous Bi-Fe-Ca-O film with 0.3 m thick grown on the Si single crystal was studied by the anomalous x-ray scattering (AXS) method. This relatively new method using the anomalous dispersion effect of a specific constituent element in a film reduces the difficulty in the subtraction process of a substrate intensity for estimating the net intensity of a thin film, which becomes a main cause of errors of the resultant data in the conventional method. The environmental radial distribution functions around Bi and Fe in the amorphous Bi-Fe-Ca-O film were determined, from which the structural features were obtained

    Magnetic Excitations in the Quasi-1D Ising-like Antiferromagnet TlCoCl3_3

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    Neutron inelastic scattering measurements have been performed in order to investigate the magnetic excitations in the quasi-1D Ising-like antiferromagnet TlCoCl3_3. We observed the magnetic excitation, which corresponds to the spin-wave excitation continuum corresponding to the domain-wall pair excitation in the 1D Ising-like antiferromagnet. According to the Ishimura-Shiba theory, we analyzed the observed spin-wave excitation, and the exchange constant 2J2J and the anistropy Ï”\epsilon were estimated as 14.7 meV and 0.14 in TlCoCl3_3, respectively.Comment: 2 pages, 3 figures, jpsj2.cls, to be published in J. Phys. Soc. Jpn. Vol.75 (2006) No.

    Forty-Four Pass Fibre Optic Loop for Improving the Sensitivity of Surface Plasmon Resonance Sensors

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    A forty-four pass fibre optic surface plasmon resonance sensor that enhances detection sensitivity according to the number of passes is demonstrated for the first time. The technique employs a fibre optic recirculation loop that passes the detection spot forty- four times, thus enhancing sensitivity by a factor of forty-four. Presently, the total number of passes is limited by the onset of lasing action of the recirculation loop. This technique offers a significant sensitivity improvement for various types of plasmon resonance sensors that may be used in chemical and biomolecule detections.Comment: Submitted for publication; patent disclosure submitte

    Towards Identifying and closing Gaps in Assurance of autonomous Road vehicleS - a collection of Technical Notes Part 1

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    This report provides an introduction and overview of the Technical Topic Notes (TTNs) produced in the Towards Identifying and closing Gaps in Assurance of autonomous Road vehicleS (Tigars) project. These notes aim to support the development and evaluation of autonomous vehicles. Part 1 addresses: Assurance-overview and issues, Resilience and Safety Requirements, Open Systems Perspective and Formal Verification and Static Analysis of ML Systems. Part 2: Simulation and Dynamic Testing, Defence in Depth and Diversity, Security-Informed Safety Analysis, Standards and Guidelines

    Measuring our universe from galaxy redshift surveys

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    Galaxy redshift surveys have achieved significant progress over the last couple of decades. Those surveys tell us in the most straightforward way what our local universe looks like. While the galaxy distribution traces the bright side of the universe, detailed quantitative analyses of the data have even revealed the dark side of the universe dominated by non-baryonic dark matter as well as more mysterious dark energy (or Einstein's cosmological constant). We describe several methodologies of using galaxy redshift surveys as cosmological probes, and then summarize the recent results from the existing surveys. Finally we present our views on the future of redshift surveys in the era of Precision Cosmology.Comment: 82 pages, 31 figures, invited review article published in Living Reviews in Relativity, http://www.livingreviews.org/lrr-2004-
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