19,633,798 research outputs found

    On the linear increase of the flux tube thickness near the deconfinement transition

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    We study the flux tube thickness of a generic Lattice Gauge Theory near the deconfining phase transition. It is well known that the effective string model predicts a logarithmic increase of the flux tube thickness as a function of the interquark distance for any confining LGT at zero temperature. It is perhaps less known that this same model predicts a linear increase in the vicinity of the deconfinement transition. We present a precise derivation of this result and compare it with a set of high precision simulations in the case of the 3d gauge Ising model.Comment: 20 pages, 4 figures, minor changes. Accepted for publication in JHE

    Synthesis of porous silicates

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    The issues of importance and future concern in the synthesis of porous silicates and porous materials that contain a large fraction of silica, e.g. zeolites and other crystalline molecular sieves, are reviewed. The thermodynamics of zeolite synthesis are discussed, including a detailed thermodynamic analysis of the synthesis of pure-silica ZSM-5. The kinetics of porous silicate synthesis are reviewed, with particular emphasis on the control of porous structure formation through the use of organic structure-directing agents. Ordered mesoporous materials are discussed in the context of distinguishing their features from zeolites in order to describe further the unique properties of each class of material. Finally, several unresolved issues in the understanding of the synthesis process are outlined, the resolutions of which would aid in the synthesis of porous silicates by design

    Perturbation hydrogen-atom spectrum in deformed space with minimal length

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    We study energy spectrum for hydrogen atom with deformed Heisenberg algebra leading to minimal length. We develop correct perturbation theory free of divergences. It gives a possibility to calculate analytically in the 3D case the corrections to ss-levels of hydrogen atom caused by the minimal length. Comparing our result with experimental data from precision hydrogen spectroscopy an upper bound for the minimal length is obtained.Comment: 9 pages, 3 figure

    Fermionic quasinormal modes for two-dimensional Ho\v{r}ava-Lifshitz black holes

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    To obtain fermionic quasinormal modes, the Dirac equation for two types of black holes is investigated. For the first type of black hole, the quasinormal modes have continuous spectrum with negative imaginary part that provides the stability of black hole geometry. For the second type of the black hole, the quasinormal modes have discrete spectrum and are completely imaginary. This type of the black hole appears to be stable for arbitrary masses of fermion field perturbations.Comment: 13 pages, no figure
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