From pub_off@ictp.trieste.it Tue Jun 26 16:32:10 2001
Date: Tue, 12 Jun 2001 09:50:10 +0200
From: Publications Office 
To: preprints@ictp.trieste.it
Subject: 2nd List of 2001 ICTP Preprints

+---------------------- "ICTP SCIENTIFIC PREPRINTS LIST" ------------------+ |      Automatic e-mail delivery service of recent ICTP Preprints Titles | | SOURCES can be retrieved from  URL:   http://www.ictp.trieste.it/~pub_off | HARD COPIES are available by e-mail request to:  pub_off@ictp.trieste.it | by quoting the ICTP preprint number and giving your full postal address +--------------------------------------------------------------------------+

2001LIST-2

This is the second list of 2001 ICTP preprints which are available.

+--------------------------------------------------------------+
ICTP Preprint No.IC2001014
DISCRETE BOSE-EINSTEIN SPECTRA
by Valentin I. Vlad and Nicholas Ionescu-Pallas 
ABSTRACT: The Bose-Einstein energy spectrum of a quantum gas, confined in a 
rigid cubic box, is shown to become discrete and strongly dependent on the 
box geometry (size $L$), temperature, $T$ and atomic mass, $A_{at}$ in the 
region of small $\gamma = A_{at}TV^{1/3}$. This behavior is the consequence 
of the random state degeneracy in the box. Furthermore, we demonstrate that 
the total energy does not obey the conventional law any longer, but a new 
law, which depends on  and on the quantum gas fugacity. This energy law

imposes a faster decrease to zero than it is classically expected, for

$\gamma\to 0$. The lighter the gas atoms, the higher the temperatures or 
the box size, for the same effects in the discrete Bose-Einstein regime. 


ICTP Preprint No.IC2001015
ABSENCE OF HIGHER ORDER CORRECTIONS TO NONCOMMUTATIVE CHERN-SIMONS COUPLING
by Ashok Das and M.M. Sheikh-Jabbari
ABSTRACT: We analyze the structure of noncommutative pure Chern-Simons

theory systematically in the axial gauge. We show that there is no IR/UV
mixing in this theory in this gauge. In fact, we show, using the usual
BRST identities as well as the identities following from vector
supersymmetry, that this is a free theory. As a result, the tree level
Chern-Simons coefficient is not renormalized. It also holds that the
Chern-Simons coefficient is not modified at finite temperature. 


ICTP Preprint No.IC2001016
THE LAGRANGIAN DESCRIPTION OF REPRESENTATIONS OF THE POINCARE GROUP
by Cestmir Burdik, Anatoly Pashnev and Mirian Tsulaia
ABSTRACT: The construction of lagrangians describing the various 
representations of the Poincare group is given in terms of the BRST 
approach.


ICTP Preprint No.IC2001018
ON A $p-$LAPLACE NEUMANN PROBLEM WITH ASYMPTOTICALLY ASYMMETRIC 
PERTURBATIONS
by Mohssine Alif and Pierpaolo Omari
ABSTRACT: We study the solvability of the quasilinear elliptic 
problem   $$\left\{   \begin{array}{cl}
-\Delta_p u  =  f(u) - h(x) & \mbox{ in }\, \Omega,\\
{\partial u} /{\partial \nu} = 0%\frac{\partial u} {\partial n} = 0
{}& \mbox{ on }\, \partial \Omega, \end{array} \right.$$
in the case where $f$ lies in some sense below the first
nontrivial branch of the Dancer-Fu\v c\'{\i}k spectrum $\Sigma$ of
the Neumann $p$-Laplacian. The interaction  with $\Sigma$ is
controlled imposing a condition on a primitive of $f$ and assuming  
the existence of upper and lower solutions without any
special ordering.


ICTP Preprint No.IC2001019
NONCOMMUTATIVE o$_{\star }$(N) AND usp$_{\star }$(2N) ALGEBRAS
AND THE CORRESPONDING GAUGE FIELD THEORIES
by I. Bars, M.M. Sheikh-Jabbari and M.A. Vasiliev
ABSTRACT: The extension of the noncommutative u$_{\star}(N)$ Lie algebra to
noncommutative orthogonal and symplectic Lie algebras is studied. Using an
anti-automorphism of the star-matrix algebra, we show that the u$_{\star} 
(N)$ can consistently be restricted to o$_{\star }(N)$ and usp$_{\star}

(N) $ algebras that have new mathematical structures. We give explicit
fundamental matrix representations of these algebras, through which the
formulation for the corresponding noncommutative gauge field theories are
obtained. In addition, we present a D-brane configuration with an
orientifold which realizes geometrically our algebraic construction, thus
embedding the new noncommutative gauge theories in superstring theory in 
the presence of a constant background magnetic field. Some algebraic
generalizations that may have applications in other areas of physics are
also discussed.


ICTP Preprint No.IC2001021
A NOTE ON THERMODYNAMICS AND HOLOGRAPHY OF MOVING GIANT GRAVITONS
by Donam Youm
ABSTRACT: In our previous work (Phys. Rev. D63, 085010, hep-th/0011290), we 
showed that the brane universe on the giant graviton moving in the near-
horizon background of the dilatonic D$(6-p)$-brane is described by the

mirage cosmology.  We study thermodynamic properties of the moving giant 
graviton by applying thermodynamics of cosmology and the recently proposed
holographic principles of cosmology.  We find that the Fischler-Susskind 
holographic bound is satisfied by the closed brane universe on the moving 
giant graviton with $p>3$.  The Bekenstein and the Hubble entropy bounds 
and the recently proposed Verlinde's holographic principle applied to the 
brane universe on the giant graviton are also studied.


ICTP Preprint No.IC2001023
NONLINEAR POLARIZATION EFFECTS IN A BIREFRINGENT SINGLE MODE OPTICAL FIBER
by G.C. Ishiekwene, S.Y. Mensah and C.S. Brown
ABSTRACT: The nonlinear polarization effects in a birefringent single mode 
optical fiber is studied using Jacobi elliptic functions. We find that the 
polarization state of the propagating beam depends on the initial 
polarization as well as the intensity of the input light in a complicated 
way. The Stokes polarization parameters are either periodic or aperiodic 
depending on the value of the Jacobian modulus. Our calculations suggest 
that the effective beat length of the fiber can become infinite at a higher 
critical value of the input power when polarization dependent losses are 
considered.


ICTP Preprint No.IC2001026
AMPLIFICATION OF STRONG-GROUND MOTION IN THE CITY OF ZAGREB, CROATIA, 
ESTIMATED BY COMPUTATION OF SYNTHETIC SEISMOGRAMS
by Ivan Lokmer, Marijan Herak, Giuliano F. Panza and Franco Vaccari
ABSTRACT: A hybrid technique consisting of modal summation and subsequent 
finite differences modelling is applied for the computation of synthetic 
accelerograms along a profile crossing the city of Zagreb, the capital of 
Croatia. Assuming known source geometry, the amplification properties of 
underlying soil may be determined by comparison of synthetics and their

response spectra computed for a simple bedrock model with the ones obtained 
under the assumption of a realistic laterally varying local model. The peak 
ground acceleration is larger by a factor of up to 3.5 than when compared 
with the value obtained for the bedrock model. The amplification of the

response spectra is most prominent for frequencies below 2 Hz, and 
increases sharply to the SW from the mapped fault running through the 
centre of the city.


ICTP Preprint No.IC2001028
THE CARDY-VERLINDE FORMULA AND ASYMPTOTICALLY FLAT CHARGED BLACK HOLES
by Donam Youm
ABSTRACT: We show that the modified Cardy-Verlinde formula without the

Casimir effect term is satisfied by asymptotically flat charged black holes 
in arbitrary dimensions.  Thermodynamic quantities of the charged black

holes are shown to satisfy the energy-temperature relation of a 
two-dimensional CFT, which supports the claim in our previous work (Phys. 
Rev. D61, 044013, hep-th/9910244) that thermodynamics of charged black

holes in higher dimensions can be effectively described by two-dimensional 
theories.  We also check the Cardy formula for the two-dimensional 
black hole compactified from a dilatonic charged black hole in higher 
dimensions.


ICTP Preprint No.IC2001032
THE CARDY-VERLINDE FORMULA AND TOPOLOGICAL AdS-SCHWARZSCHILD BLACK HOLES
by Donam Youm
ABSTRACT: We consider the brane universe in the background of the 
topological AdS-Schwarzschild black holes.  The induced geometry of the

brane is that of a flat or an open radiation dominated FRW-universe.  Just 
like the case of a closed radiation dominated FRW-universe, the temperature 
and entropy are simply expressed in terms of the Hubble parameter and 
its time derivative when the brane crosses the black hole horizon.  
We propose the modified Cardy-Verlinde formula which is valid for any 
values of the curvature parameter $k$ in the Friedmann equations.


ICTP PREPRINT NO.IC2001043
PATTERN RECOGNITION METHODOLOGIES AND DETERMINISTIC EVALUATION OF SEISMIC 
HAZARD: A STRATEGY TO INCREASE EARTHQUAKE PREPAREDNESS
by Antonella Peresan, Giuliano F. Panza, Alexander I. Gorshkov
and Abdelkrim Aoudia
ABSTRACT: Several algorithms, structured according to a general pattern-
recognition scheme, have been developed for the space-time identification 
of strong events. Currently, two of such algorithms are applied to the

Italian territory, one for the recognition of earthquake-prone areas and 
the other, namely CN algorithm, for earthquake prediction purposes. These 
procedures can be viewed as independent experts, hence they can be combined 
to better constrain the alerted seismogenic area. We examine here the 
possibility to integrate CN intermediate-term medium-range earthquake 
predictions, pattern recognition of earthquake-prone areas and 
deterministic hazard maps, in order to associate CN Times of Increased

Probability (TIPs) to a set of appropriate scenarios of ground motion. The 
advantage of this procedure mainly consists in the time information 
provided by predictions, useful to increase preparedness of safety measures 
and to indicate a priority for detailed seismic risk studies to be 
performed at a local scale.


ICTP Preprint No.IC2001047
SUPERCONDUCTIVITY NEAR FERROMAGNETISM IN MgCNi$_3$
by H. Rosner, R. Weht, M. Johannes, W.E. Pickett and E. Tosatti
ABSTRACT: Superconductivity and ferromagnetism have been believed to be
incompatible over any extended temperature range until certain 
specific examples - RuSr$_2$GdCu$_2$O$_8$ and UGe$_2$ - have arisen
in the past 2-3 years.  The discovery of superconductivity above
8 K in MgCNi$_3$, which is primarily the ferromagnetic element Ni
and is strongly exchange-enhanced, provides a probable new and
different example.  This compound is shown here to be near ferromagnetism,
requiring only hole-doping by 12\% substitution of Mg by Na or Li.
This system will provide the means to probe coupling, and possible
coexistence, of these two forms of collective behavior without the 
requirement of pressure.
















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