Résultat de la recherche
3 résultat(s) recherche sur le tag 'Dark matter' 
Affiner la recherche Générer le flux rss de la recherche
Partager le résultat de cette recherche Interroger des sources externesالدراسة الديناميكية لنموذج الطاقة المظلمة اللزجة في الكوسمولوجيا الكلاسيكية و الجاذبية الكوانتية الحلقية. / سارة بن الشيخ
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) Catégories : Arabe
الفيزياءTags : ?????? ??????? ???????? ??????? ?????? 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 : 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)
Catégories : Arabe
الفيزياءTags : ?????? ??????? ???????? ??????? ?????? 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 : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=10880 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité بنا/4322 بنا/4322 Thèse Bibliothèque principale Thèses Disponible
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) Catégories : Français - Anglais
PhysiqueTags : 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 : 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)
Catégories : Français - Anglais
PhysiqueTags : 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 : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=11025 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité BEN/7376 BEN/7376 Thèse Bibliothèque principale Thèses Disponible
Titre : Viscous modified chaplygin in classical and loop quantum cosmology. Type de document : texte imprimé Auteurs : Dalel Aberkane, Auteur ; Nourreddine Mebarki, Directeur de thèse Editeur : جامعة الإخوة منتوري قسنطينة Année de publication : 2018 Importance : 80 f. Format : 30 cm. Note générale : 2 copies imprimées disponibles
Langues : Anglais (eng) Catégories : Français - Anglais
PhysiqueTags : Cosmologie Quantique des Boucles Energie Noir Gaz De Chaplygin Matière Noir Seconde Viscosité Loop Quantum Cosmology Dark Energy Chaplygin Gas Dark Matter Bulk Viscosity ???????????? ???????? ??????? ?????? ??????? ??? ???????? ??????
??????? ??????? ???????Index. décimale : 530 Physique Résumé : In this thesis, we chose VMCG with a specific bulk viscosity pressure as a toy model for our universe to explore its behavior at present time, when fitted to recent observational data, and at late time to check whether it suffers from singularities or not.
The Eos parameters are constrained for a suitable model that describes the current universe. We also evaluate the evolution of the state and deceleration parameters at present and early universe and determine their present values to deduce if the model is consistent or not with observation data and theoretical predictions. The values are compared to those of other well accepted models. Then, we probe the dynamical behavior of our toy model at early and late time in the LQC framework especially as the model suffers from the Big Bang singularity.
The model is found suitable to describe the current universe with consistent present values of both state and deceleration parameters ∈ (−0.76, −0.74) , ∈ (−0.60, −0.57). At large scale, the VMCG has no future singularities and its equation of state is nearly equivalent to cosmological constant ( = -1). The sound speed takes a constant value different from zero as a difference between a dynamical fluid model and an inert cosmological constant model. The VMCG discussed here reproduces the main results of the standard model without
assuming a priori the existence of cosmological constant, the problems related to fine-tuning and coincidence problems are solved and the value of the redshift where ( ≈ ) for both
= 0.01and = 0.0001 is z = 0.75. At LQC background and at large scale the results found are the same as those of classical background and at small scale the Big Bang singularity problem is solved and replaced by a
bounce, at large scale the stability of the model does not depend on the EoS parameter and VMCG universe solutions depend only on .
Diplôme : Doctorat En ligne : ../theses/physique/ABE7290.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=10905 Viscous modified chaplygin in classical and loop quantum cosmology. [texte imprimé] / Dalel Aberkane, Auteur ; Nourreddine Mebarki, Directeur de thèse . - [S.l.] : جامعة الإخوة منتوري قسنطينة, 2018 . - 80 f. ; 30 cm.
2 copies imprimées disponibles
Langues : Anglais (eng)
Catégories : Français - Anglais
PhysiqueTags : Cosmologie Quantique des Boucles Energie Noir Gaz De Chaplygin Matière Noir Seconde Viscosité Loop Quantum Cosmology Dark Energy Chaplygin Gas Dark Matter Bulk Viscosity ???????????? ???????? ??????? ?????? ??????? ??? ???????? ??????
??????? ??????? ???????Index. décimale : 530 Physique Résumé : In this thesis, we chose VMCG with a specific bulk viscosity pressure as a toy model for our universe to explore its behavior at present time, when fitted to recent observational data, and at late time to check whether it suffers from singularities or not.
The Eos parameters are constrained for a suitable model that describes the current universe. We also evaluate the evolution of the state and deceleration parameters at present and early universe and determine their present values to deduce if the model is consistent or not with observation data and theoretical predictions. The values are compared to those of other well accepted models. Then, we probe the dynamical behavior of our toy model at early and late time in the LQC framework especially as the model suffers from the Big Bang singularity.
The model is found suitable to describe the current universe with consistent present values of both state and deceleration parameters ∈ (−0.76, −0.74) , ∈ (−0.60, −0.57). At large scale, the VMCG has no future singularities and its equation of state is nearly equivalent to cosmological constant ( = -1). The sound speed takes a constant value different from zero as a difference between a dynamical fluid model and an inert cosmological constant model. The VMCG discussed here reproduces the main results of the standard model without
assuming a priori the existence of cosmological constant, the problems related to fine-tuning and coincidence problems are solved and the value of the redshift where ( ≈ ) for both
= 0.01and = 0.0001 is z = 0.75. At LQC background and at large scale the results found are the same as those of classical background and at small scale the Big Bang singularity problem is solved and replaced by a
bounce, at large scale the stability of the model does not depend on the EoS parameter and VMCG universe solutions depend only on .
Diplôme : Doctorat En ligne : ../theses/physique/ABE7290.pdf Format de la ressource électronique : Permalink : https://bu.umc.edu.dz/md/index.php?lvl=notice_display&id=10905 Exemplaires (1)
Code-barres Cote Support Localisation Section Disponibilité ABE/7290 ABE/7290 Thèse Bibliothèque principale Thèses Disponible
