80,181 research outputs found

    The Possible JPCIG=2++2+J^{PC}I^G=2^{++}2^+ State X(1600)

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    The interesting state X(1600) with JPCIG=2++2+J^{PC}I^G=2^{++}2^+ can't be a conventional qqˉq \bar q meson in the quark model. Using a mixed interpolating current with different color configurations, we investigate the possible existence of X(1600) in the framework of QCD finite energy sum rules. Our results indicate that both the "hidden color" and coupled channel effects may be quite important in the multiquark system. We propose several reactions to look for this state.Comment: axodraw.sty include

    Coarse-Grained Picture for Controlling Complex Quantum Systems

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    We propose a coarse-grained picture to control ``complex'' quantum dynamics, i.e., multi-level-multi-level transition with a random interaction. Assuming that optimally controlled dynamics can be described as a Rabi-like oscillation between an initial and final state, we derive an analytic optimal field as a solution to optimal control theory. For random matrix systems, we numerically confirm that the analytic optimal field steers an initial state to a target state which both contains many eigenstates.Comment: jpsj2.cls, 2 pages, 3 figure files; appear in J. Phys. Soc. Jpn. Vol.73, No.11 (Nov. 15, 2004

    Phonon-phason coupling in icosahedral quasicrystals

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    From relaxation simulations of decoration-based quasicrystal structure models using microscopically based interatomic pair potentials, we have calculated the (usually neglected) phonon-phason coupling constant. Its sign is opposite for the two alloys studied, i-AlMn and i-(Al,Cu)Li; a dimensionless measure of its magnitude relative to the phonon and phason elastic constants is of order 1/10, suggesting its effects are small but detectable. We also give a criterion for when phonon-phason effects are noticeable in diffuse tails of Bragg peaks.Comment: 7 pages, LaTeX, uses Europhys Lett macros (included
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