http://depot.umc.edu.dz/handle/123456789/13100 Thu, 30 Apr 2026 21:15:42 GMT 2026-04-30T21:15:42Z http://depot.umc.edu.dz/handle/123456789/14042 Rotating Charged Cosmic Strings from Seiberg-Witten Non Commutative Geometry Menacera, L.; Aissaouia, H. En utilisant la géométrie non commutative de l’espace-temps de Seiberg-Witten, pour la gravitation de jauge d’une corde cosmique charge en rotation on a déterminé explicitement en fonction du paramètre de la non commutativité de l’espace-temps les différentes expressions des veirbeins et les connections de spin non commutatifs nécessaires pour l’étude de l’effet tunnel. En utilisant la méthode BKW, pour des particules spinorielles, on a pu montrer la forme de l’expression de la température de Hawking au voisinage de l’horizon. Wed, 14 Dec 2016 00:00:00 GMT http://depot.umc.edu.dz/handle/123456789/14042 2016-12-14T00:00:00Z http://depot.umc.edu.dz/handle/123456789/14041 Solution of the Klein-Gordon oscillator in cosmic string space-time for scalar potentials Messai, N.; Boumali, A. We study in this work the exact solutions of two-dimensional relativistic particuls of spin-0 in the cosmic string background under the effects of scalar potentials as modification in the momentum operator 𝑝𝜇→𝑝𝜇−𝑒𝐴𝜇 and in the mass term 𝑚→𝑚+𝑆(𝜌). In this way, we solve the Klein-Gordon oscillator (KG) and find the energy levels for bound states. Finally the dependance of the scalar potentials interaction with the angular frequency and the energy spectrum has been discussed. Thu, 15 Dec 2016 00:00:00 GMT http://depot.umc.edu.dz/handle/123456789/14041 2016-12-15T00:00:00Z http://depot.umc.edu.dz/handle/123456789/14040 Iintroduction to(𝑹) gravity and applications Mansour, H.; Si Lakhal, B. Recent cosmological data show that the universe is expanding at an accelerating rate. This contradicts the results of general relativity, at least for a Universe composed only of matter. To attack this problem, two general ways have been taken: introducing a new type of energy (such as the cosmological constant Λ, dark energy) or modifying the theory of gravitation. So, several extensions to the theory of gravitation were proposed in order to preserve the positive results of Einstein’s Theory of general relativity. The simplest extension is the so called (𝑅) gravity which consists in replacing the Ricci scalar 𝑅 by a function 𝑓 of it. Here, we review 𝑓(𝑅) gravity, a modification to general relativity, are all about modifying the Einstein-Hilbert action and taking it to higher orders in the Ricci scalar. There are three versions of (𝑅) modified gravity: Metric, Palatini and Metric-affine gravity. In this work we will briefly review these versions of (𝑅) modified gravity. We will be essentially interested in examining how does (𝑅) gravity affects the behavior of a charged compact star. Wed, 14 Dec 2016 00:00:00 GMT http://depot.umc.edu.dz/handle/123456789/14040 2016-12-14T00:00:00Z http://depot.umc.edu.dz/handle/123456789/14039 PT symmetry in non commutative geometry Leghrib, I.; Mebarki, N.; Moulla, H. A PT symmetric and pseudo hermitien hamiltonien is constructed in the context of the seubery. Written non commutatitive space-time and some physical application are presented. Thu, 15 Dec 2016 00:00:00 GMT http://depot.umc.edu.dz/handle/123456789/14039 2016-12-15T00:00:00Z