Subject: 1999 LIST - 15, ICTP preprints
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1999LIST-15
This is the fifteenth list of 1999 ICTP preprints which are available.
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ICTP Preprint No.IC99153
ON THE CHARACTERISTICS EQUATION OF A NON-LINEAR, AGE-STRUCTURED
POPULATION MODEL
by N.I. Akinwande
ABSTRACT: In this work, we obtain a general sufficient condition for
which the zeros of the transcendental characteristics equation, arising
from the perturbation of the equilibrium state of the non-linear, age-
structured population model of Gurtin and MacCamy (1974), with maximum
life-expectancy $\Omega$ incorporated, will lie on the left half
plane.
This is the condition which guarantees the local assymptotic stability
of the equilibrium state.
ICTP Preprint No.IC99161
DYNAMICAL RELAXATION OF THE CP PHASES IN NEXT-TO-MINIMAL SUPERSYMMETRY
by D.A. Demir
ABSTRACT: After promoting the phases of the soft masses to dynamical
fields corresponding to Goldstone bosons of spontaneously broken global
symmetries in the supersymmetry breaking sector, the next-to-minimal
supersymmetric model is found to solve the $\mu$ problem and the strong
CP problem simultaneously with an invisible axion. The domain wall
problem persists in the form of axionic domain formation. Relaxation
dynamics of the physical CP-violating phases is determined only by
the short-distance physics and their relaxation values are not
necessarily close to the CP-conserving points. Consequently, the
solution
of the supersymmetric CP problem may require heavy enough superpartners
and nonminimal flavor structures, where the latter may be also relevant
for avoiding the formation of axionic domain walls.
ICTP Preprint No.IC99162
ON THE DEFORMATION OF $\Lambda$-SYMMETRY IN B-FIELD BACKGROUND
by M.M. Sheikh-Jabbari
ABSTRACT: In this note we will show that the $\Lambda$ symmetry, namely
the $U(1)$ symmetry of the open string sigma model which relates the
B-
field and the $U(1)$ gauge field of a brane to each other, is deformed
to
a noncommutative version in a constant B-field background.
ICTP Preprint No.IC99164
SPECTRUM OF q-DEFORMED SCHRODINGER EQUATION
by Jian-zu Zhang
ABSTRACT: The energy spectrum of q-deformed Schrodinger equation is
demonstrated. This spectrum includes an exponential factor with new
quantum numbers, the $q$-exciting number and the scaling index. The
pattern of quark and lepton masses is qualitatively explained by such
a $q$-deformed spectrum in a composite model.
ICTP Preprint No.IC99165
CP VIOLATION AS A PROBE OF FLAVOR ORIGIN IN SUPERSYMMETRY
by D.A. Demir, A. Masiero and O. Vives
ABSTRACT: We address the question of the relation between supersymmetry
breaking and the origin of flavor in the context of CP violating
phenomena. We prove that, in the absence of the
Cabibbo-Kobayashi-Maskawa
phase, a general Minimal Supersymmetric Standard Model with all
possible
phases in the soft-breaking terms, but no new flavor structure beyond
the usual Yukawa matrices, can never give a sizeable contribution
to $\varepsilon_K$, $\varepsilon^\prime/\varepsilon$ or hadronic $B^0$
CP
asymmetries. Observation of supersymmetric contributions to CP
asymmetries in B decays would hint at a non-flavor blind mechanism of
supersymmetry breaking.
ICTP Preprint No.IC99166
DERIVATION OF THE POLYAKOV ACTION
by M. Kachkachi
ABSTRACT: We develop another method to get the Polyakov action
that is: the solution of the conformal Ward identity on a Riemann
surface $\Sigma$. We find that this action is the sum of two terms:
the first one is expressed in terms of the projective connection and
produces the diffeomorphism anomaly and the second one is anomaly and
contains the globally defined zero modes of the Ward identity. The
explicit expression of this action is given on the complex plane.
ICTP Preprint No.IC99167
ANOMALY CANCELLATION CONDITION IN ABELIAN LATTICE GAUGE THEORIES
by Hiroshi Suzuki
ABSTRACT: We analyze the general solution of the Wess-Zumino
consistency
condition in abelian lattice gauge theories, without taking the
classical continuum limit. We find that, if the anomaly density is a
local pseudo-scalar field on the lattice, the non-trivial anomaly is
always proportional to the anomaly coefficient in the continuum
theory. The possible extension of this result to non-abelian
theories is briefly discussed.
ICTP Preprint No.IC99172
IONOSPHERIC PROFILE PARAMETERS B0 AND B1 AND THE EQUATORIAL ELECTROJET
by O.K. Obrou, S.M. Radicella and J.O. Adeniyi
ABSTRACT: B0 and B1 are parameters used in the International Reference
Ionosphere (IRI) model for the calculation of the F region bottom side
profiles. For this study, we have used ionograms recorded at Korhogo,
an
equatorial station. The parameter $\Delta$H obtained from the magnetic
data recorded during the International Equatorial Electrojet Year
(IEEY)
in West African is used to describe the strength of the equatorial
electrojet. This work covers the years 1993 and 1994, two years of low
solar activity.
ICTP Preprint No.IC99173
HYDRODYNAMICAL FLUCTUATIONS IN SMOOTH SHEAR FLOWS
by G.D. Chagelishvili, G.R. Khujadze and J.G. Lominadze
ABSTRACT: Background of hydrodynamical fluctuations in a
intrinsically/stochastically forced, laminar, uniform shear
flow is studied. The employment of so-called nonmodal mathematical
analysis makes it possible to represent the background of fluctuations
in a new light and to get more insight into the physics of its
formation. The basic physical processes responsible for the formation
of vortex and acoustic wave fluctuation backgrounds are analyzed.
Interplay of the processes at low and moderate shear rates is
described. Three-dimensional vortex fluctuations around a given
macroscopic state are numerically calculated. The correlation
functions
of the fluctuations of physical quantities are analyzed. It is shown
that there exists subspace ${\cal D}_{\bf k}$ in the wave-number space
(${\bf k}$-space) that is limited externally by spherical surface with
radius $k_{\nu} \equiv {A/ \nu}$ (where $A$ is the velocity shear
parameter, $\nu$ -- the kinematic viscosity) in the nonequilibrium open
system under study. The spatial Fourier harmonics of vortex as well as
acoustic wave fluctuations are strongly subjected by flow shear (by the
open character of the system) at wave-numbers satisfying the
condition $k<$ be a closed convex nonempty subset of a real normed
linear space and let $T : K\mapsto K\>$ be a Lipschitz
pseudocontraction
such that $F(T)\cap K\neq\emptyset$. We introduce the concept of
double-
sequence iteration processes and prove the strong convergence of such
iteration processes to a fixed point of $T\>$ in $K$. Related results
deal with the strong convergence of the said iteration processes to a
solution of the operator equation $Ax = f\>$ where $f\in R(A)\>$ is an
arbitrary but fixed vector and $A\>$ is an accretive operator
mapping $E\>$ to $E$.
ICTP Preprint No.IC99178
QUANTUM GROUP U$_{\bf q}$(D$_{\bf\ell}$) SINGULAR VECTORS
IN POINCARE-BIRKHOFF-WITT BASIS
by V.K. Dobrev and M. EL Falaki
ABSTRACT: We give explicit expressions for the singular vectors
of $U_q(D_\ell)$ in terms of the Poincare-Birkhoff-Witt (PBW) basis. We
relate these expressions with those in terms of the simple
root vectors.
ICTP Preprint No.IC99180
VALIDATION OF TEC MODELS OVER AN EQUATORIAL STATION
by A.A. Willoughby, S.M. Radicella, J.O. Adeniyi and B. Nava
ABSTRACT: Total electron content (TEC) data obtained by the Faraday
technique at Ghana (5.63$^\circ$N, 359.81$^\circ$E) have been used for
the validation of two ionospheric models for the purpose of TEC
prediction in the equatorial region. The two models considered are the
International Reference Ionosphere (IRI) and the NeQuick. Predicted
values from both models for a year each of high and low solar
activities
are presented. The results indicate that, at low solar activity, IRI
overestimates TEC during day and nighttime hours at all seasons,
while NeQuick underestimates the parameter in January and October from
0800 - 1700 hrs. At high solar activity, there is a reasonably close
agreement between both models and the observed data from sunrise to
sunset. Generally, both IRI and NeQuick models tend to predict higher
TEC values from 0000 - 0500hrs at low solar activity. Some suggestions
are made for the improvement of the models.
ICTP Preprint No.IC99181
FOCK REPRESENTATIONS OF THE SUPERALGEBRA
sl(n+1$|$m), ITS QUANTUM ANALOGUE U$_{\bf q}$[sl(n+1$|$m)]
AND RELATED QUANTUM STATISTICS
by T.D. Palev, N.I. Stoilova and J. Van der Jeugt
ABSTRACT: Fock space representations of the Lie superalgebra
$sl(n+1|m)$
and of its quantum analogue $U_q[sl(n+1|m)]$ are written down. The
results are based on a description of these superalgebras via creation
and annihilation operators. The properties of the underlying statistics
are briefly discussed.
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