8,460 research outputs found
On the sine-Gordon--Thirring equivalence in the presence of a boundary
In this paper, the relationship between the sine-Gordon model with an
integrable boundary condition and the Thirring model with boundary is discussed
and the reflection -matrix for the massive Thirring model, which is related
to the physical boundary parameters of the sine-Gordon model, is given. The
relationship between the the boundary parameters and the two formal parameters
appearing in the work of Ghoshal and Zamolodchikov is discussed.Comment: 14 pages, Latex, to be published in Int. J. Mod. Phys. A. Two
references adde
Modes of zonal mean temperature variability 20–100 km from the TIMED/SABER observations
In this study we investigate the spatial variabilities of the zonal mean
temperature (20–100 km) from the TIMED (Thermosphere, Ionosphere,
Mesosphere, Energetics and Dynamics)/SABER (Sounding of the Atmosphere using
Broadband Emission Radiometry) satellite using the empirical
orthogonal functions (EOFs). After removing the climatological annual mean, the
first three EOFs are able to explain 87.0% of temperature variabilities. The
primary EOF represents 74.1% of total anomalies and is dominated by the
north–south contrast. Patterns in the second and third EOFs are related to
the semiannual oscillations (SAO) and mesospheric temperature inversions
(MTI), respectively. The quasi-biennial oscillation (QBO) component is also decomposed
into the seventh EOF with contributions of 1.2%. Last, we use the first
three modes and annual mean temperature to reconstruct the data. The result
shows small differences are in low latitude, which increase with latitude in
the middle stratosphere and upper mesosphere
Phase diagram of the frustrated, spatially anisotropic S=1 antiferromagnet on a square lattice
We study the S=1 square lattice Heisenberg antiferromagnet with spatially
anisotropic nearest neighbor couplings , frustrated by a
next-nearest neighbor coupling numerically using the density-matrix
renormalization group (DMRG) method and analytically employing the
Schwinger-Boson mean-field theory (SBMFT). Up to relatively strong values of
the anisotropy, within both methods we find quantum fluctuations to stabilize
the N\'{e}el ordered state above the classically stable region. Whereas SBMFT
suggests a fluctuation-induced first order transition between the N\'{e}el
state and a stripe antiferromagnet for and an
intermediate paramagnetic region opening only for very strong anisotropy, the
DMRG results clearly demonstrate that the two magnetically ordered phases are
separated by a quantum disordered region for all values of the anisotropy with
the remarkable implication that the quantum paramagnetic phase of the spatially
isotropic - model is continuously connected to the limit of
decoupled Haldane spin chains. Our findings indicate that for S=1 quantum
fluctuations in strongly frustrated antiferromagnets are crucial and not
correctly treated on the semiclassical level.Comment: 10 pages, 10 figure
Synthesis, characterization and crystal structure of a dioxomolybdenum(VI) complex derived from N’-(2-hydroxy-4-diethaylaminobenzylidene)-4-hydroxybenzohydrazide
Reaction of [MoO2(acac)2] (where acac = acetylacetonate) with N’-(2-hydroxy-4-diethaylaminobenzylidene)-4-hydroxybenzohydrazide (H2L) in methanol afforded a methanol-coordinated mononuclear molybdenum(VI) oxo complex, [MoO2L(MeOH)]. Crystal and molecular structure of the complex were determined by single crystal X-ray diffraction method. The complex was further characterized by elemental analysis and FT-IR spectra. Single crystal X-ray structural studies indicate that the hydrazone ligand coordinates to the MoO2 core through enolate oxygen, phenolate oxygen and azomethine nitrogen. The Mo atom in the complex is in octahedral coordination. Thermal stability of the complex has also been studied. KEY WORDS: Molybdenum complex, Hydrazone ligand, Crystal structure, X-ray diffraction, Thermal property Bull. Chem. Soc. Ethiop. 2014, 28(3), 409-414.DOI: http://dx.doi.org/10.4314/bcse.v28i3.1
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