2,945 research outputs found
Difference L operators and a Casorati determinant solution to the T-system for twisted quantum affine algebras
We propose factorized difference operators L(u) associated with the twisted
quantum affine algebras U_{q}(A^{(2)}_{2n}),U_{q}(A^{(2)}_{2n-1}),
U_{q}(D^{(2)}_{n+1}),U_{q}(D^{(3)}_{4}). These operators are shown to be
annihilated by a screening operator. Based on a basis of the solutions of the
difference equation L(u)w(u)=0, we also construct a Casorati determinant
solution to the T-system for U_{q}(A^{(2)}_{2n}),U_{q}(A^{(2)}_{2n-1}).Comment: 15 page
Nonlinear integral equations for thermodynamics of the sl(r+1) Uimin-Sutherland model
We derive traditional thermodynamic Bethe ansatz (TBA) equations for the
sl(r+1) Uimin-Sutherland model from the T-system of the quantum transfer
matrix. These TBA equations are identical to the ones from the string
hypothesis. Next we derive a new family of nonlinear integral equations (NLIE).
In particular, a subset of these NLIE forms a system of NLIE which contains
only a finite number of unknown functions. For r=1, this subset of NLIE reduces
to Takahashi's NLIE for the XXX spin chain. A relation between the traditional
TBA equations and our new NLIE is clarified. Based on our new NLIE, we also
calculate the high temperature expansion of the free energy.Comment: 24 pages, 4 figures, to appear in J. Phys. A: Math. Ge
Nonlinear integral equations for the thermodynamics of the sl(4)-symmetric Uimin-Sutherland model
We derive a finite set of nonlinear integral equations (NLIE) for the
thermodynamics of the one-dimensional sl(4)-symmetric Uimin-Sutherland model.
Our NLIE can be evaluated numerically for arbitrary finite temperature and
chemical potentials. We recover the NLIE for sl(3) as a limiting case. In
comparison to other recently derived NLIE, the evaluation at low temperature
poses no problem in our formulation. The model shows a rich ground-state phase
diagram. We obtain the critical fields from the T to zero limit of our NLIE. As
an example for the application of the NLIE, we give numerical results for the
SU(4) spin-orbital model. The magnetic susceptibility shows divergences at
critical fields in the low-temperature limit and logarithmic singularities for
zero magnetic field.Comment: 32 pages, 7 figures; references added, minor corrections, final
versio
Locally continuously perfect groups of homeomorphisms
The notion of a locally continuously perfect group is introduced and studied.
This notion generalizes locally smoothly perfect groups introduced by Haller
and Teichmann. Next, we prove that the path connected identity component of the
group of all homeomorphisms of a manifold is locally continuously perfect. The
case of equivariant homeomorphism group and other examples are also considered.Comment: 14 page
From the quantum Jacobi-Trudi and Giambelli formula to a nonlinear integral equation for thermodynamics of the higher spin Heisenberg model
We propose a nonlinear integral equation (NLIE) with only one unknown
function, which gives the free energy of the integrable one dimensional
Heisenberg model with arbitrary spin. In deriving the NLIE, the quantum
Jacobi-Trudi and Giambelli formula (Bazhanov-Reshetikhin formula), which gives
the solution of the T-system, plays an important role. In addition, we also
calculate the high temperature expansion of the specific heat and the magnetic
susceptibility.Comment: 18 pages, LaTeX; some explanations, 2 figures, one reference added;
typos corrected; to appear in J. Phys. A: Math. Ge
Deep Near-Infrared Observations and Identifications of Chandra Sources in the Orion Molecular Cloud 2 and 3
We conducted deep NIR imaging observations of the Orion molecular cloud 2 and
3 using QUIRC on the 88-inch telescope of the University of Hawaii. Our
purposes are 1) to generate a comprehensive NIR source catalog of these star
forming clouds, and 2) to identify the NIR counterpart of the Chandra X-ray
sources that have no counterpart in the 2MASS catalog. Our J-, H-, and K-band
observations are about 2 mag deeper than those of 2MASS, and well match the
current Chandra observation. We detected 1448 NIR sources, for which we derived
the position, the J-, H-, and K-band magnitude, and the 2MASS counterpart.
Using this catalog, we identified the NIR counterpart for about 42% of the
2MASS-unIDed Chandra sources. The nature of these Chandra sources are discussed
using their NIR colors and spatial distributions, and a dozen protostar and
brown dwarf candidates are identified.Comment: 39 pages, 9 postscript figures, accepted for publication in A
A simplification of boundary element model with rotational symmetry in electromagnetic field analysis
A simplification method for the boundary element model with rotational symmetry is described. When the boundary element model has a rotational symmetry, the region to be treated for boundary integrations can be reduced to the fundamental boundary surface. This reduction is possible because the coefficient matrix of the final simultaneous equations for the model can be transformed to a block diagonal matrix by a transformation matrix using spatial eigenmodes. The simplification reduces the computation time and storage capacity because the coefficient matrix of the final simultaneous equations of the boundary element method is dense. Computation results for a four-wire method demonstrate the applicability of the proposed simplification method </p
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