19-21 February 2019
"Sapienza" University, Phys. Dept. Marconi
Europe/Rome timezone

A Graceful Exit for the Cosmological Constant Damping Scenario

21 Feb 2019, 12:13
17m
Aula Amaldi ("Sapienza" University, Phys. Dept. Marconi)

Aula Amaldi

"Sapienza" University, Phys. Dept. Marconi

Rome
talk General Relativity and Cosmology General Relativity & Cosmology

Speaker

Mr Kévin Nguyen (Vrije Universiteit Brussel)

Description

Abstract: I will present a simple and generic class of scalar-tensor theories that successfully realize dynamical damping of the effective cosmological constant, therefore providing a viable dynamical resolution of the fine-tuning cosmological constant problem. In contrast to early versions of this approach, the models considered do not suffer from unacceptable variations of Newton's constant, as one aims at a small but strictly positive late-time curvature. I will then show that the original fine-tuning issue is traded for a hierarchy of couplings, and further suggest a way to naturally generate this hierarchy based on fermion condensation and softly broken field shift symmetry. This talk is based on Phys. Rev. D 98, 124031 (2018), arXiv:1810.12336.

Primary author

Mr Kévin Nguyen (Vrije Universiteit Brussel)

Co-author

Prof. Oleg Evnin (Vrije Universiteit Brussel and Chulalongkorn U. )

Presentation Materials