2 résultat(s) recherche sur le tag 'Matière sombre'    

Quelques problËmes en relativité et cosmologie / Amine Benachour  

Public ISBD Titre : Quelques problËmes en relativité et cosmologie : Théorie d’einstein-cartan comme alternative au problème de la matière sombre, théorie F(R) et transformation de Lorentz à l’échelle macroscopique Type de document : texte imprimé Auteurs : Amine Benachour, Auteur ; Sami Ryad Zouzou, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2018 Importance : 98 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles Langues : Français (fre) Tags : Einstein-Cartan theory  Spherical symmetry  Exact solutions  Mass formula  Dark matter  f(R) theory  Ricci scalar  Common solutions  Lorentz transformation  Length contraction  Thought experiment  Tape measure  Simultaneity  Macroscopic scale  Théorie d’Einstein-Cartan  Symétrie sphérique  Solutions exactes  Formule de masse  Matière sombre  Théorie f(R)  Scalaire de Ricci  Solutions communes  Transformation de Lorentz  Contraction des longueurs  Expérience de pensée  Mètre ruban  Simultanéité  Echelle macroscopique  ????? ???????? ?????  ????? ????  ???? ?????????  ????? ??????  ?????? ???????  ????? f(R)  ???? ????????  ???? ??????  ????? ?????  ???? ???????  ???? ????  ????? Index. décimale : 530 Physique Résumé : Some current issues in cosmology lead us to consider theories of gravitation other than general relativity. It is in this context that this thesis is being taken by considering first the Einstein-Cartan theory for static and spherically symmetric spacetime where obtaining exact solutions has led to a general formula linking the internal mass of an object with spherical symmetry to its external mass, highlighting a difference in mass that would likely to provide an explanation for the dark matter problem in the universe. Another theory of gravitation which has been studied in this thesis often proposed as an alternative to the problem of dark energy; is the f(R) theory where the emphasis has been placed on its close link with general relativity by demonstrating the necessary and sufficient condition for a metric to be a solution of the two theories; whose consequences made possible the construction of f(R) theories equivalent to general relativity for a specific form of the Ricci scalar; and set the conditions on the parameters of a given model to have such equivalence. Finally, following the analysis of a thought experiment involving the measurement of the distance between two observers in motion by a tape measure, certain problems related to the application of the Lorentz transformation at the macroscopic scale have also been investigated and solved. Diplôme : Doctorat en sciences En ligne : ../theses/physique/BEN7376.pdf Format de la ressource électronique : pdf Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=11025 Quelques problËmes en relativité et cosmologie : Théorie d’einstein-cartan comme alternative au problème de la matière sombre, théorie F(R) et transformation de Lorentz à l’échelle macroscopique [texte imprimé] / Amine Benachour, Auteur ; Sami Ryad Zouzou, Directeur de thèse . - [S.l.] : جامعة الإخوة منتوري قسنطينة, 2018 . - 98 f. ; 30 cm. 2 copies imprimées disponibles Langues : Français (fre) Tags : Einstein-Cartan theory  Spherical symmetry  Exact solutions  Mass formula  Dark matter  f(R) theory  Ricci scalar  Common solutions  Lorentz transformation  Length contraction  Thought experiment  Tape measure  Simultaneity  Macroscopic scale  Théorie d’Einstein-Cartan  Symétrie sphérique  Solutions exactes  Formule de masse  Matière sombre  Théorie f(R)  Scalaire de Ricci  Solutions communes  Transformation de Lorentz  Contraction des longueurs  Expérience de pensée  Mètre ruban  Simultanéité  Echelle macroscopique  ????? ???????? ?????  ????? ????  ???? ?????????  ????? ??????  ?????? ???????  ????? f(R)  ???? ????????  ???? ??????  ????? ?????  ???? ???????  ???? ????  ????? Index. décimale : 530 Physique Résumé : Some current issues in cosmology lead us to consider theories of gravitation other than general relativity. It is in this context that this thesis is being taken by considering first the Einstein-Cartan theory for static and spherically symmetric spacetime where obtaining exact solutions has led to a general formula linking the internal mass of an object with spherical symmetry to its external mass, highlighting a difference in mass that would likely to provide an explanation for the dark matter problem in the universe. Another theory of gravitation which has been studied in this thesis often proposed as an alternative to the problem of dark energy; is the f(R) theory where the emphasis has been placed on its close link with general relativity by demonstrating the necessary and sufficient condition for a metric to be a solution of the two theories; whose consequences made possible the construction of f(R) theories equivalent to general relativity for a specific form of the Ricci scalar; and set the conditions on the parameters of a given model to have such equivalence. Finally, following the analysis of a thought experiment involving the measurement of the distance between two observers in motion by a tape measure, certain problems related to the application of the Lorentz transformation at the macroscopic scale have also been investigated and solved. Diplôme : Doctorat en sciences En ligne : ../theses/physique/BEN7376.pdf Format de la ressource électronique : pdf Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=11025

Exemplaires

Code-barres	Cote	Support	Localisation	Section	Disponibilité
aucun exemplaire

الدراسة الديناميكية لنموذج الطاقة المظلمة اللزجة في الكوسمولوجيا الكلاسيكية و الجاذبية الكوانتية الحلقية. / سارة بن الشيخ  

Public ISBD Titre : الدراسة الديناميكية لنموذج الطاقة المظلمة اللزجة في الكوسمولوجيا الكلاسيكية و الجاذبية الكوانتية الحلقية. Type de document : texte imprimé Auteurs : سارة بن الشيخ, Auteur ; نور الدين مباركي, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2018 Importance : 118 ورقة. Format : 30 سم. Note générale : 2نسخ موجودة مكتبة المركزية Langues : Arabe (ara) Tags : ?????? ???????  ???????? ??????? ??????  Bulk Viscosity  Loop Quantum Gravity  Dark Energy  Dark matter  seconde viscosité  gravité quantique des boucles  énergie sombre  matière sombre Index. décimale : 530 الفيزياء Résumé : In this thesis we have suggested two cosmological models.in the first one we have studied the dynamical behaviors and stability properties of a flat space FRW universe filled with pressureless dark matter and viscous dark energy in the context of standard classical and loop quantum cosmology. Assuming that the dark energy has a constant bulk viscosity, it is found that the bulk viscosity effects influence only the quintessence model case leading to the existence of a viscous late time attractor solution of de-Sitter type, whereas, the quantum geometry effects influence the phantom model case where the big rip singularity is removed. Moreover, compared with the more recent data, our results of the Hubble parameter as a function of the redshift are in a good agreement. However, in the second model we have studied the dynamical behaviors and stability properties of a flat space FRW universe filled with pressureless dark matter and viscous dark energy in the context of loop quantum cosmology. Assuming that the dark energy has bulk viscosity in the general form, we have found there exists under some appropriate parameters a stable late time viscous dark energy dominated solution of de Sitter type. the problem of future singularity (big rip) will never occur in this scenario. Diplôme : Doctorat En ligne : ../theses/physique/ABEN4322.pdf Format de la ressource électronique : pdf Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=10880 الدراسة الديناميكية لنموذج الطاقة المظلمة اللزجة في الكوسمولوجيا الكلاسيكية و الجاذبية الكوانتية الحلقية. [texte imprimé] / سارة بن الشيخ, Auteur ; نور الدين مباركي, Directeur de thèse . - [S.l.] : جامعة الإخوة منتوري قسنطينة, 2018 . - 118 ورقة. ; 30 سم. 2نسخ موجودة مكتبة المركزية Langues : Arabe (ara) Tags : ?????? ???????  ???????? ??????? ??????  Bulk Viscosity  Loop Quantum Gravity  Dark Energy  Dark matter  seconde viscosité  gravité quantique des boucles  énergie sombre  matière sombre Index. décimale : 530 الفيزياء Résumé : In this thesis we have suggested two cosmological models.in the first one we have studied the dynamical behaviors and stability properties of a flat space FRW universe filled with pressureless dark matter and viscous dark energy in the context of standard classical and loop quantum cosmology. Assuming that the dark energy has a constant bulk viscosity, it is found that the bulk viscosity effects influence only the quintessence model case leading to the existence of a viscous late time attractor solution of de-Sitter type, whereas, the quantum geometry effects influence the phantom model case where the big rip singularity is removed. Moreover, compared with the more recent data, our results of the Hubble parameter as a function of the redshift are in a good agreement. However, in the second model we have studied the dynamical behaviors and stability properties of a flat space FRW universe filled with pressureless dark matter and viscous dark energy in the context of loop quantum cosmology. Assuming that the dark energy has bulk viscosity in the general form, we have found there exists under some appropriate parameters a stable late time viscous dark energy dominated solution of de Sitter type. the problem of future singularity (big rip) will never occur in this scenario. Diplôme : Doctorat En ligne : ../theses/physique/ABEN4322.pdf Format de la ressource électronique : pdf Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=10880

Exemplaires

Code-barres	Cote	Support	Localisation	Section	Disponibilité
aucun exemplaire