Théorie

Observational constraints on inflationary potentials within the quantum collapse framework

The inflationary paradigm is the most successful model for the
generation of primordial perturbations. These perturbations have a
purely quantum origin, while the inhomogeneities and anisotropies
observed today exhibit a classical behavior. The model called Continuous
Spontaneous Localization (CSL) is a proposed mechanism to solve the
measurement problem in quantum mechanics. In this presentation, we will
analyze the theoretical predictions resulting from incorporating the CSL

Stochastic inflation in a general field space

Inflationary models in non-trivial field spaces encoded by their non-canonical kinetic terms have attracted attentions recently. We have then extended the so-called stochastic formalism to such a general case. This formalism investigates the fluctuation of inflatons treating them as Brownian motions. This work highlights the involved problem of this formalism, related with the mathematical uncertainty of the definition of noise integral. Comparing the correlation functions in the stochastic formalism and quantum field theory, we clarify that this uncertainty cannot be rem

Perturbative dynamics of massive gluons

Lattice simulations of Yang-Mills theories and QCD in the Landau gauge have

demonstrated that the gluon propagator saturates at vanishing momentum. This can

be modeled by a massive deformation of the corresponding Faddeev-Popov

Lagrangian known as the Curci-Ferrari model. The latter does not modify the known

ultraviolet regime of the theory and provides a successful perturbative description of

essential aspects of the non-Abelian dynamics in the infrared regime, where, in

Fermion masses, quark mixing and Flavor Changing Neutral Currents from a gauged SU(3)_F family symmetry

Within a broken local gauge vector-like $SU(3)_F$ family symmetry, we address the problem of quark masses and mixing,  and study some rare flavor violating processes induced by the new gauge bosons, which can generate transitions between different families and so introduce "Flavor Changing Neutral Currents"(FCNC) couplings at tree level. We find out that some of the most dangerous FCNC processes, like for instance; 

Galileon p-form theories

I will discuss the generalization to p-forms of the Galileon idea: to
construct the most general theory of an (abelian gauge invariant) p-form
with (strictly) second order field equations. Such theory have recently be
fully classified for space-time dimension strictly smaller than 12. The
covariantization of these theories will also be discussed.

Conformal symmetry in the Standard Model and Gravity

I will discuss prospects of formulating simple extensions of the standard model and gravity that exhibit local Weyl symmetry in the ultraviolet. The principal advantage of such constructions is that they naturally address the gauge and gravitational hierarchy problem. Furthermore,  I will argue that Cartan-Einstein gravity provides a natural framework for conformal symmetry, as this theory contains torsion vector which can be interpreted as the Weyl vector.

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