Title: Introduction à la Géométrie $k-$ Symplectique
Author: Azzouz Awane
Comments: 11 pages, no figures
Abstract:
One of the major motivations that have to led to the $k-$ symplectic geometry is to give a geometrical formalism of Numbu's generalised Hamiltonian dynamics. We give here, he specific features of the $k-$ symplectic geometry by putting the accent on Hamiltonian formalism associated. The relationships between Hamiltonian systems of the $k-$ symplectic mechanics and Numbu's dynamic systems are given.

Title: Systèmes Integrables de Calogero
Authors: Mohammed Kessabi & Hanane Sebbata
Comments: 22 pages, no figures
Abstract:
Dans cette revue, on se propose d'\'{e}tudier une cat\'{e}gorie de syst\`{e}mes hamiltoniens compl\`{e}tement int\'{e}grables connus sous le nom de syst\`{e}mes de Calogero-Moser. De tels syst\`{e}mes sont constitu\'{e}s d'un nombre fini de particules ponctuelles identiques se mouvant sur une ligne et soumises \`{a} des potentiels d'interactions coulombiens ou harmoniques.

AJMP/0412[ ps, pdf] :

Title: UV/IR Mixing, Noncommutative instabilites and Closed Strings
Author: Esperanza Lopez
Comments: 5 pages, no figures
Abstract:
The leading UV/IR mixing effects on noncommutative field theories modify the dispersion relations and, depending on their sign, may cause the appearance of unstable modes. For noncommutative gauge theories on D-branes, this phenomenon is able to capture important information about the closed string spectrum of the parent string theory. We analyse noncommutative D-branes on nonsupersymmetric orbifolds and twisted circle backgrounds. We find that the sign of the leading UV/IR mixing effects is governed by the mass gap between the lowest modes in the NSNS and RR closed string towers. For noncommutative D3-branes at orbifolds we obtain an stronger result: a one to one correspondence between noncommutative instabilities and closed string tachyons.

AJMP/0413 [ ps, pdf] :

Title: Sp(0) and Orientifolds
Author: Karl Landsteiner
Comments: 5 pages, no figures
Abstract:
I discuss the geometric engineering perspective of the solution to the discrepancy between matrix model and field theory effective superpotential in the case of {\it None} gauge theories with matter in the antisymmetric representation.

Title: On string backgrounds and (logarithmic) CFT
Author: Jorgen Rasmussen
Comments: 5 pages, no figures
Abstract:
We discuss the link between string backgrounds and the associated world-sheet CFTs. In the search for new backgrounds and CFTs, Penrose limits and Lie algebra ontractions are important tools. The Nappi-Witten construction and the recently discovered logarithmic CFT by Bakas and Sfetsos, are considered as illustrations. We also speculate on possible extensions.

Title: Some spectral properties of the Pauli-Hamiltonian and of its square root
Author: Allal Ghanmi
Comments: 6 pages, no figures
Abstract:
The so-called Dirac-Hamiltonian is realized as the square root of the Pauli-Hamiltonian with uniform magnetic field. Some $L^2$-spectral properties of both operators are discussed.

Title: Aspects of Inflation in Brane Physics
Author: M.Bennai
Comments: 6 pages, no figures
Abstract:
We study the brane effect on the behaviour of universe in inflationary theory. We also study the modification of slow-roll inflation in the brane scenario for arbitrary inflaton potential, independently of the dynamics of the bulk. We show that in this scenario, the Friedmann equations governing the dynamics of scalar field are modified by an supplementary term which depend on the ratio of the density of matter $\rho $ and the tension of the brane $\lambda $We calculate the scale factor for a chaotic potential in braneworld formalism, and show that it has an exponential form as it may be for an inflationary model.

Title: Dissociation of a boosted quarkonium in quark-gluon plasma
Author: Sidi Cherkawi Benzahra
Comments: 3 pages, no figures
Abstract:
I consider the dissociation of a boosted quarkonium in a quark-gluon plasma. This dissociation is due to absorption of a thermal gluon. I discuss the dissociation in terms of the velocity of the quarkonium and the temperature of the quark-gluon plasma. I compare this dissociation rate to the one calculated without including the velocity of the quarkonium.

Title: The Hierarchy of Hamiltonians for Spherical Woods-saxon potential
Author: J. Sadeghi & M. R. Pahlavani
Comments: 5 pages, no figures
Abstract:
The three dimensional Woods-Saxon potential is studied within the context of Supersymmetry Quantum Mechanics. We obtain hierarchy of hamiltonians related to Woods-Saxon superpotentials that have not been determined yet. In the basis of supersymmetry method \cite{w17}, we obtain the shape invariant superfamily related to original woods-Saxon potential. Also we derive $n$-th ground state energy, $\epsilon_{0}^{n}$ corresponding to $n$-th superpotential associated to generalized Woods-Saxon potential. The results obtained here are consistent with results obtained from another ways \cite{w24}. The generalized Woods-Saxon potential obtained here completely shape invariant. By application of this method,it is possible to solve the schr\"{o}dinger equation for this potential.

AJMP/0419 [ ps, pdf] :

Title: Generalized KdV- and mKdV-type bilinear equations
Author: Peter A Clarkson, Xing-Biao Hu & Xian-Min Qian
Comments: 7 pages, no figures
Abstract:
Generalized KdV-type and mKdV-type bilinear equations are considered. Under certain conditions, we show that the equations have one- or two-soliton solutions. Furthermore, some special forms of mKdV-type equations are studied in some detail. The conditions under which 3-soliton-like solutions exist are given. Some examples are illustrated.

AJMP/0420 [ pdf] :

Title: Lie Group Method for Solving the MHD Flow around a Cylinder in Crossed Electric and Strong Magnetic Fields
Author: Mina B. Abd-el-Malek & Samy M. A. El-Mansi
Comments: 11 pages, no figures
Abstract:
This paper is devoted to an analytical study of the laminar longitudinal MHD-flow which arises when a cylinder of infinite length and arbitrary electrical conductivity is placed into a conducting fluid which is subjected to crossed electric and strong magnetic fields that are homogeneous at infinity and perpendicular to the axis of the cylinder. We establish the complete Lie group of infinitesimal symmetries. The Lie group method, which is applied here, reduces the number of independent variables. Finally, the obtained system of ordinary differential equations with the appropriate corresponding conditions are solved analytically. The flow field, the induced magnetic field and the resulting forces on the cylinder are calculated.