19,633,798 research outputs found
On the linear increase of the flux tube thickness near the deconfinement transition
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
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
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 -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
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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