18,232 research outputs found

    Application of quantitative microscopy to ceramics

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    Case studies were made of the graphite structures in cast iron. The form, size, distribution, and direction of the structures are described. Microscopic and stereoscopic techniques are discussed

    ppK- bound states from Skyrmions

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    The bound kaon approach to the strangeness in the Skyrme model is applied to investigating the possibility of deeply bound ppKppK^- states. We describe the ppKppK^- system as two-Skyrmion around which a kaon field fluctuates. Each Skyrmion is rotated in the space of SU(2) collective coordinate. The rotational motions are quantized to be projected onto the spin-singlet proton-proton state. We derive the equation of motion for the kaon in the background field of two Skyrmions at fixed positions. From the numerical solution of the equation of motion, it is found that the energy of KK^- can be considerably small, and that the distribution of KK^- shows molecular nature of the ppKppK^- system. For this deep binding, the Wess-Zumino-Witten term plays an important role. The total energy of the ppKppK^- system is estimated in the Born-Oppenheimer approximation. The binding energy of the ppKppK^- state is B.E.126B.E.\simeq 126 MeV. The mean square radius of the pppp subsystem is 1.6\sqrt{}\simeq 1.6 fm.Comment: Oct 2007, 15 pages, 8 figures; added references, corrected typo

    Non-Abelian Stokes Theorem and Quark Confinement in SU(3) Yang-Mills Gauge Theory

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    We derive a new version of SU(3) non-Abelian Stokes theorem by making use of the coherent state representation on the coset space SU(3)/(U(1)×U(1))=F2SU(3)/(U(1)\times U(1))=F_2, the flag space. Then we outline a derivation of the area law of the Wilson loop in SU(3) Yang-Mills theory in the maximal Abelian gauge (The detailed exposition will be given in a forthcoming article). This derivation is performed by combining the non-Abelian Stokes theorem with the reformulation of the Yang-Mills theory as a perturbative deformation of a topological field theory recently proposed by one of the authors. Within this framework, we show that the fundamental quark is confined even if G=SU(3)G=SU(3) is broken by partial gauge fixing into H=U(2)H=U(2) just as GG is broken to H=U(1)×U(1)H=U(1) \times U(1). An origin of the area law is related to the geometric phase of the Wilczek-Zee holonomy for U(2). Abelian dominance is an immediate byproduct of these results and magnetic monopole plays the dominant role in this derivation.Comment: 14 pages, Latex, no figures, version accepted for publication in Mod. Phys. Lett. A (some comments are added in the final parts

    Realization of Strong Coupling Fixed Point in Multilevel Kondo Models

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    Impurity four- and six-level Kondo model, in which an ion is tunneling among four- and six-stable points and interacting with surrounding conduction electrons, are investigated by using the perturbative and numerical renormalization group methods. It is shown that purely orbital Kondo effects occur at low temperatures in these systems which are direct generalizations of the Kondo effect in the so-called two-level system. This result offers a good explanation for the enhanced and magnetically robust Sommerfeld coefficient observed in SmOs_4Sb_12 and some other filled-skutterudites.Comment: 3 pages, 3 figures, for proceedings of ASR-WYP-2005. To be published in Journal of Physical Society Japan supplemen

    Future of Ultraviolet Astronomy Based on Six Years of IUE Research

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    Physical insights into the various astronomical objects which were studied using the International Ultraviolet Explorer (IUE) satellite. Topics covered included galaxies, cool stars, hot stars, close binaries, variable stars, the interstellar medium, the solar system, and IUE follow-on missions