Centre de Physique Théorique

Agenda

Vendredi 17 novembre 2017

XIIIe Ecole de Cosmologie

XIIIe Ecole de Cosmologie

Ecole thématique du CNRS organisée par François Bouchet (IAP) et Roland Triay (CPT)

This school, which is open to international students, has as objectives the reciprocal upgrade and the development of a multidisciplinary community on the research lines promoted by the CNRS. It will favour the transfer of methods/techniques and the development of a multidisciplinary community that is either connected or interested in the massive data processing and statistical analysis. It will train new generations of researchers, notably on the basis of the existing Planck community. They will thus be able to take up the many challenges of all kinds that these ambitious projects involve, on theoretical aspects, instrumental ones and analysis of massive and complex data. The competencies (already obtained) in the processing of data are of interest to other scientific communities which have already expressed their interest, which will lead to the creation of networks for exchanges and collaborations.

14h00 – 15h00, Amphi 5 du CPT

Holographic self-tuning of the cosmological constant

Francesco Nitti (APC, Paris)

I will present a brane-world setup, based on the gauge/gravity
duality, in which the four-dimensional cosmological constant is
neutralized by a dynamical self-adjustment mechanism. The model consists in a five-dimensional Einstein-Dilaton gravity coupled to a
four-dimensional brane on which ordinary matter and gauge fields are
localized. The brane position in the bulk is determined dynamically by the junction conditions, and flat-brane solutions exist for generic values of the brane vacuum energy. A regime with emergent 4-dimensional gravity is possible, due to the presence of an induced gravity term on the brane. The emergent 4d graviton acquires an effective mass, and a five-dimensional regime may exist at large and/or small scales. Analysis of scalar fluctuations allows to formulate conditions for perturbative stability of the flat solutions, which can be met in a broad range of the model parameters.

Agenda