From pub_off@ictp.trieste.it Tue Jun 26 16:32:10 2001 Date: Tue, 12 Jun 2001 09:50:10 +0200 From: Publications OfficeTo: 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. | +--------------------------------------------------------------------------+ | To SUBSCRIBE/UNSUBSCRIBE from this service send an e-mail | To: preprints-request@ictp.trieste.it | Subject: (LEAVE IT EMPTY) | and write in the body of the message | ^^^^^^^^^^^ | SUBSCRIBE your_email_address or | UNSUBSCRIBE your_email_address | depending on your choice (FOR EXAMPLE: subscribe john@ictp.trieste.it) +--------------------------------------------------------------------------+