Thesis

Coupled tachyonic dark energy: a test in the Euclid era

• Call:

  PT-CERN Call 2021/2

• Academic Year:

  2021

• Domain:

  Astroparticle Physics

• Supervisor:

  Alberto Rozas-Fernandez

• Co-Supervisor:

  Francesco Pace

• Institution:

  FCUL (Universidade de Lisboa)

• Host Institution:

  IA - Instituto de Astrofísica e Ciências do Espaço

• Abstract:

  The main goal of ESA's Euclid space mission, to be launched in 2022, is to understand the origin of the observed late-time accelerated expansion of the Universe. One tantalising theoretical possibility is to describe the acceleration and the formation of structure in models in which dark energy interacts directly with dark matter. The goals of the proposed thesis are two-fold. First, study the evolution of cosmological structure in the coupled tachyonic dark energy scenario, forecasting Euclid’s ability in testing this hypothesis. For this purpose, we shall consider conformally coupled, disformally coupled, together with models which simultaneously make use of both couplings. The different models will be tested both at background and linear level against the most recent observational data. Second, study the full non-linear regime, producing the first N-body simulations of the coupled tachyon and making therefore the first detailed study of non-linear structure formation under the coupled tachyon hypothesis.