Astrophysical and Local Tests of the Einstein Equivalence Principle
PT-CERN Call 2020/2
Universidade do Porto
Centro de Astrofísica da Universidade do Porto
The Standard Model of particle physics is one of the most well succeeded theories known to physicists. It has endured a number of tests proving to be resilient and experimentally accurate theory. However, there are several reasons that lead physicists believe that this theory is still lacking something. For this reason, theories beyond the SM are being explored. Some of these theories lead to remarkable consequences, such as predicting violations of the Einstein equivalence principle. The Einstein Equivalence Principle (EEP, which Einstein formulated in 1907) is the cornerstone of General Relativity (only formulated in 1915) but also of a broader class known as metric theories of gravity. Recent developments, including quantum interferometric tests and dedicated space missions, promise to revolutionize the field of local tests of the EEP and dramatically improve their current sensitivity. This thesis will explore new synergies between these imminent new local tests of the EEP and ongoing or planned astrophysical and cosmological tests: some of these directly test the EEP, while others only test GR on various scales. We will explore relevant paradigms (including string theory and scenarios with and without screening mechanisms), develop a taxonomy for various model classes, and study how they are further constrained by experiments such as MICROSCOPE and ACES, in combination with astrophysical data from ESPRESSO, ALMA and other facilities. The work will also be directly relevant for the science case of several ELT instruments, as well as Euclid and the SKA.