Chern-Simons matrix models and Stieltjes-Wigert polynomials

Employing the random matrix formulation of Chern-Simons theory on Seifert manifolds, we show how the Stieltjes-Wigert orthogonal polynomials are useful in exact computations in Chern-Simons matrix models. We construct a biorthogonal extension of the Stieltjes-Wigert polynomials, not available in the literature, necessary to study Chern-Simons matrix models when the geometry is a lens space. We also discuss several other results based on the properties of the polynomials: the equivalence between the Stieltjes-Wigert matrix model and the discrete model that appears in q-2D Yang-Mills and the relationship with Rogers-Szego polynomials and the corresponding equivalence with an unitary matrix model. Finally, we also give a detailed proof of a result that relates quantum dimensions with averages of Schur polynomials in the Stieltjes-Wigert ensemble.Comment: 25 pages, AMS-LaTe

Magic N=2 supergravities from hyper-free superstrings

We show by explicit construction the existence of various four dimensional models of type II superstrings with N=2 supersymmetry, purely vector multiplet spectrum and no hypermultiplets. Among these, two are of special interest, at the field theory level they correspond to the two exceptional N=2 supergravities of the magic square that have the same massless scalar field content as pure N=6 supergravity and N=3 supergravity coupled to three extra vector multiplets. The N=2 model of the magic square that is associated to N=6 supergravity is very peculiar since not only the scalar degrees of freedom but all the bosonic massless degrees of freedom are the same in both theories. All presented hyper-free N=2 models are based on asymmetric orbifold constructions with N=(4,1) world-sheet superconformal symmetry and utilize the 2d fermionic construction techniques. The two exceptional N=2 models of the magic square are constructed via a "twisting mechanism" that eliminates the extra gravitini of the N=6 and N=3 extended supergravities and creates at the same time the extra spin-1/2 fermions and spin-1 gauge bosons which are necessary to balance the numbers of bosons and fermions. Theories of the magic square with the same amount of supersymmetry in three and five space-time dimensions are constructed as well, via stringy reduction and oxidation from the corresponding four-dimensional models.Comment: 27 page

Dualités, construction de modèles et polynômes biorthogonaux en théorie des supercordes

Dans le premier chapitre de cette thèse nous développons des règles formelles pour l'oxydation et la réduction dimensionnelle de théories incluant le secteur bosonique des théories de supergravité. Ceci nous permet de mettre en évidence la symétrie de leurs équations du mouvement sous des superalgèbres de Borcherds. Nous présentons ensuite une construction explicite du groupe de dualité non-perturbatif SU(4,n) des modèles de corde avec supersymétrie d'espace-temps N=6 en dimension trois ainsi qu'une discussion de la c-map pour plusieurs modèles perturbatifs exacts de cordes obtenus par la construction fermionique.Enfin, nous effectuons des rappels sur la théorie de Chern-Simons et le lien existant avec les modèles de matrices. On y présente nos résultats sur la construction des polynômes biorthogonaux de Stieltjes-Wigert qui sont utiles à l'étude de la théorie de Chern-Simons formulée sur les espaces lenticulaires.PARIS-BIUSJ-Thèses (751052125) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF