Thesis

The nature of the Universe's acceleration

• Call:

  IDPASC Portugal - PHD Programme 2015

• Academic Year:

  2015 / 2016

• Domains:

  General Relativity | Cosmology

• Supervisor:

  Nelson Nunes

• Co-Supervisor:

  Antonio da Silva

• Institution:

  Faculdade de Ciências - Universidade de Lisboa

• Host Institution:

  Instituto de Astrofisica e Ciencias do Espaco

• Abstract:

  Over a decade has passed since supernova observations first indicated a remarkable property of our Universe: it is currently undergoing a period of accelerated expansion. In the intervening time, this acceleration has been confirmed by a range of complementary observational probes, such as those of the cosmic microwave background and of large scale structure and baryonic acoustic oscillations. Yet, despite this plethora of observational evidence, the theoretical model that explains this phase of evolution remains unknown. In this project we aim to take a step towards determining the theoretical model of present-day acceleration by analysing an extremely general class of models, which can have intriguing theoretical properties, to evaluate if they can also be observationally consistent. This investigation has both a theoretical and a hands on data component. A combination of analytical and numerical methods is, therefore, required to construct and test these models against current and forthcoming data. This study is extremely timely given the current push to understand theoretical models concerning dark energy and the cosmological constant in time for them to be confronted by the data of the Euclid mission.