702 research outputs found
On Type-I Quantum Affine Superalgebras
The type-I simple Lie-superalgebras are and . We study
the quantum deformations of their untwisted affine extensions
and . We identify additional
relations between the simple generators (``extra -Serre relations") which
need to be imposed to properly define \uqgh and . We
present a general technique for deriving the spectral parameter dependent
R-matrices from quantum affine superalgebras. We determine the R-matrices for
the type-I affine superalgebra in various representations,
thereby deriving new solutions of the spectral-dependent Yang-Baxter equation.
In particular, because this algebra possesses one-parameter families of
finite-dimensional irreps, we are able to construct R-matrices depending on two
additional spectral-like parameters, providing generalizations of the
free-fermion model.Comment: 23 page
Solutions of the Yang-Baxter Equation with Extra Non-Additive Parameters II: }
The type-I quantum superalgebras are known to admit non-trivial one-parameter
families of inequivalent finite dimensional irreps, even for generic . We
apply the recently developed technique to construct new solutions to the
quantum Yang-Baxter equation associated with the one-parameter family of irreps
of , thus obtaining R-matrices which depend not only on a
spectral parameter but in addition on further continuous parameters. These
extra parameters enter the Yang-Baxter equation in a similar way to the
spectral parameter but in a non-additive form.Comment: 10 pages, LaTex file (some errors in the Casimirs corrected
Affine Toda field theory on a half line
The question of the integrability of real-coupling affine toda field theory
on a half-line is addressed. It is found, by examining low-spin conserved
charges, that the boundary conditions preserving integrability are strongly
constrained. In particular, for the series of models there can be
no free parameters introduced by the boundary condition; indeed the only
remaining freedom (apart from choosing the simple condition ), resides in a choice of signs. For a special case of the boundary
condition, it is argued that the classical boundary bound state spectrum is
closely related to a consistent set of reflection factors in the quantum field
theory.Comment: 16 pages, TEX (harvmac), DTP-94/7, YITP/U-94-1
Solutions to the Quantum Yang-Baxter Equation with Extra Non-Additive Parameters
We present a systematic technique to construct solutions to the Yang-Baxter
equation which depend not only on a spectral parameter but in addition on
further continuous parameters. These extra parameters enter the Yang-Baxter
equation in a similar way to the spectral parameter but in a non-additive form.
We exploit the fact that quantum non-compact algebras such as
and type-I quantum superalgebras such as and are
known to admit non-trivial one-parameter families of infinite-dimensional and
finite dimensional irreps, respectively, even for generic . We develop a
technique for constructing the corresponding spectral-dependent R-matrices. As
examples we work out the the -matrices for the three quantum algebras
mentioned above in certain representations.Comment: 13 page
Boundary breathers in the sinh-Gordon model
We present an investigation of the boundary breather states of the
sinh-Gordon model restricted to a half-line. The classical boundary breathers
are presented for a two parameter family of integrable boundary conditions.
Restricting to the case of boundary conditions which preserve the \phi -->
-\phi symmetry of the bulk theory, the energy spectrum of the boundary states
is computed in two ways: firstly, by using the bootstrap technique and
subsequently, by using a WKB approximation. Requiring that the two descriptions
of the spectrum agree with each other allows a determination of the
relationship between the boundary parameter, the bulk coupling constant, and
the parameter appearing in the reflection factor derived by Ghoshal to describe
the scattering of the sinh-Gordon particle from the boundary.Comment: 16 pages amslate
Type-I Quantum Superalgebras, -Supertrace and Two-variable Link Polynomials
A new general eigenvalue formula for the eigenvalues of Casimir invariants,
for the type-I quantum superalgebras, is applied to the construction of link
polynomials associated with {\em any} finite dimensional unitary irrep for
these algebras. This affords a systematic construction of new two-variable link
polynomials asociated with any finite dimensional irrep (with a real highest
weight) for the type-I quantum superalgebras. In particular infinite families
of non-equivalent two-variable link polynomials are determined in fully
explicit form.Comment: the version to be published in J. Math. Phy
Hybrid procedure of bilateral pulmonary artery banding and bilateral ductal stenting in an infant with aortic atresia and interrupted aortic arch
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109582/1/ccd25424.pd
Forehead Skin Blood Flow in Normal Neonates during Active and Quiet Sleep, Measured with a Diode Laser Doppler Instrument
Changes in forehead skin blood flow during active and quiet sleep were determined in 16 healthy neonates using a recently developed semi-conductor laser Doppler flow meter without light conducting fibres. Measurements were carried out at a postnatal age varying from 5 hours to 7 days. The two sleep states could be distinguished in 17 recordings. The mean skin blood flow values during active sleep were significantly higher (p<0.01) than those during quiet sleep, the mean increase being 28.1%. The variability of the flow signal, expressed as the coefficient of variation, changed significantly from 23.1% during active sleep to 18.2% during quiet sleep
Integrable Electron Model with Correlated Hopping and Quantum Supersymmetry
We give the quantum analogue of a recently introduced electron model which
generalizes the Hubbard model with additional correlated hopping terms and
electron pair hopping. The model contains two independent parameters and is
invariant with respect to the quantum superalgebra . It is
integrable in one dimension by means of the quantum inverse scattering method.Comment: 7 pages, AmsTex fil
Quantum affine Toda solitons
We review some of the progress in affine Toda field theories in recent years,
explain why known dualities cannot easily be extended, and make some
suggestions for what should be sought instead.Comment: 16pp, LaTeX. Minor revision
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