11 research outputs found
Réussite scolaire des cégépiens offrant du tutorat aux élèves du primaire en milieux défavorisés multiethniques
Conférence présentée lors du colloque « Journée de la recherche sur la motivation au collégial » Acfas, Montréal, 10 mai 201
F-theory and M-theory perspectives on N=2 supersymmetric gauge theories in four dimensions
Deformations of the original F-theory background are proposed. These lead to
multiple new dualities and physical phenomena. We concentrate on one model
where we let seven-branes wrap a multi-centered Taub-NUT space instead of R4.
This configuration provides a successful F-theory embedding of a class of
recently proposed four-dimensional N = 2 superconformal (SCFT) \`a la Gaiotto.
Aspects of Argyres- Seiberg duality, of the new Gaiotto duality, as well as of
the branes network of Benini- Benvenuti and Tachikawa are captured by our
construction. The supergravity theory for the conformal case is also briefly
discussed. Extending our construction to the non-conformal case, we find
interesting cascading behavior in four-dimensional gauge theories with N = 2
supersymmetry. Since the analysis of this unexpected phenomenon is quite
difficult in the language of type IIB/F-theory, we turn to the type
IIA/M-theory description where the origin of the N = 2 cascade is clarified.
Using the T-dual type IIA brane language, we first start by studying the N = 1
supersymmetric cascading gauge theory found in type IIB string theory on p
regular and M fractional D3-branes at the tip of the conifold. We reproduce the
supersymmetric vacuum structure of this theory. We also show that the IIA
analog of the non-supersymmetric state found by Kachru, Pearson and Verlinde in
the IIB description is metastable in string theory, but the barrier for
tunneling to the supersymmetric vacuum goes to infinity in the field theory
limit. We then use the techniques we have developed to analyze the N = 2
supersymmetric gauge theory corresponding to regular and fractional D3-branes
on a near-singular K3, and clarify the origin of the cascade in this theory.Comment: PhD Thesi
Quaterninic Kähler manifolds, constrained instantons, and the magic square
Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal
Initial Conditions for Non-Canonical Inflation
We investigate the dynamics of homogeneous phase space for single-field
models of inflation. Inflationary trajectories are formally attractors in phase
space, but since in practice not all initial conditions lead to them, some
degree of fine tuning is required for successful inflation. We explore how the
dynamics of non-canonical inflation, which has additional kinetic terms that
are powers of the kinetic energy, can play a role in ameliorating the initial
conditions fine tuning problem. We present a qualitative analysis of
inflationary phase space based on the dynamical behavior of the scalar field.
This allows us to construct the flow of trajectories, finding that trajectories
generically decay towards the inflationary solution at a steeper angle for
non-canonical kinetic terms, in comparison to canonical kinetic terms, so that
a larger fraction of the initial-conditions space leads to inflation. Thus,
non-canonical kinetic terms can be important for removing the initial
conditions fine-tuning problem of some small-field inflation models.Comment: 15 pages, 9 figure
Attractive Lagrangians for Noncanonical Inflation
Treating inflation as an effective theory, we expect the effective Lagrangian
to contain higher-dimensional kinetic operators suppressed by the scale of UV
physics. When these operators are powers of the inflaton kinetic energy, the
scalar field can support a period of noncanonical inflation which is smoothly
connected to the usual slow-roll inflation. We show how to construct
noncanonical inflationary solutions to the equations of motion for the first
time, and demonstrate that noncanonical inflation is an attractor in phase
space for all small- and large-field models. We identify some sufficient
conditions on the functional form of the Lagrangian that lead to successful
noncanonical inflation since not every Lagrangian with higher-dimensional
kinetic operators can support noncanonical inflation. This extends the class of
known viable Lagrangians and excludes many Lagrangians which do not work.Comment: 39 pages, 9 figures. v2. Fixed typos, added reference, small changes
to examples; v3. Added discussion of field redefinitions, added references,
matches published versio
Réussite scolaire des cégépiens offrant du tutorat aux élèves du primaire en milieux défavorisés
La présente recherche a été subventionnée par le ministère de l'Éducation et de l'Enseignement supérieur dans le cadre du Programme d'aide à la recherche sur l'enseignement et l'apprentissage (PAREA).Comprend des références bibliographiques
IIA Perspective On Cascading Gauge Theory
We study the N=1 supersymmetric cascading gauge theory found in type IIB
string theory on p regular and M fractional D3-branes at the tip of the
conifold, using the T-dual type IIA description. We reproduce the
supersymmetric vacuum structure of this theory, and show that the IIA analog of
the non-supersymmetric state found by Kachru, Pearson and Verlinde in the IIB
description is metastable in string theory, but the barrier for tunneling to
the supersymmetric vacuum goes to infinity in the field theory limit. We also
comment on the N=2 supersymmetric gauge theory corresponding to regular and
fractional D3-branes on a near-singular K3, and clarify the origin of the
cascade in this theory.Comment: 43 pages, 18 figures, harvma
Réussite scolaire des cégépiens offrant du tutorat aux élèves du primaire en milieux défavorisés
La présente recherche a été subventionnée par le ministère de l'Éducation et de l'Enseignement supérieur dans le cadre du Programme d'aide à la recherche sur l'enseignement et l'apprentissage (PAREA).Comprend des références bibliographiques
Rendez-vous de l’engagement étudiant. Partie 1 : Les étudiants s’engagent dans leur communauté
Introduction sur l’engagement étudiant (motivation des étudiants, types d’activités), et présentation de projets illustrant des modes d’engagement des étudiants du collégial dans leur communauté