Cosmology of Scale Dependent Gravitation Theories

Name: Felipe de Melo Santos
Type: PhD thesis
Publication date: 15/07/2021
Advisor:

Namesort ascending Role
Davi Cabral Rodrigues Advisor *

Examining board:

Namesort ascending Role
Wiliam Santiago Hipolito Ricaldi Co advisor *
Thiago dos Santos Pereira External Examiner *
Oliver Fabio Piattella Internal Examiner *
Júlio César Fabris Internal Examiner *
Ilia Chapiro External Examiner *
Davi Cabral Rodrigues Advisor *
Armando Bartolome Bernui Leo External Examiner *

Summary: The extensions of general relativity with scale-dependent G and Λ couplings have been proposed for different motivations, but inspired, in particular, by non-trivial effects of the application of are normalization group to the gravitation. We will consider the cosmological scenario of this framework from two perspectives: developing a self-consistent action, with the necessary information to describe the dynamic of the model;andfromanumerical and observational point of view, considering the viability of the proposal from several
cosmological data. Regarding the theoretical aspects of dynamical principles, the framework is such that the back ground evolution is subject to the same equations that govern the cosmological background of the standard model (ΛCDM), but the perturbation shave corrections that depend on the scalar factor coming from the perturbation of the metric, present in other non-cosmological scenarios, and on a secondary scalar originated from consistency conditions and dependent on the trace of the energy-moment tensor. For the phenomenology of this picture, we evaluated via MCMC the data from fσ8, Supernovas type Ia, baryonic acoustico scillations, distortion in redshift space, and data from the cosmic background radiation. Our first analysis with a complete data set for a particular case in this frame suggests small deviations in the parameters of ΛCDM.

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