Dates: Thursdays 19, 26 September, 10, 17 October 2013 from 2.15pm-6pm.
Organiser: Prof. Ruth Durrer, Département de physique théorique, Université de Genève, 24, quai Ernest-Ansermet, CH-1211 Genève 4
tél. 022 379 6884; e-mail: Ruth.Durrer@unige.ch
Intervenant: Prof. Jean-Philippe Uzan, Institut d'Astrophysique de Paris
Description: Fundamental constants are a cornerstone of our physical laws. This series of lectures aims at describing their role in the laws of nature and to highlight the deep connection with Einstein's equivalence principle.
Any constant varying in space and/or time would reflect the existence of an almost massless field that couples to matter, signaling a violation of the equivalence principle. Thus, it is of importance for our understanding of gravity and of the domain of validity of general relativity to test for their constancy, in particular on astrophysical scales where the need for a dark sector is deeply connected with the validity of general relativity to describe gravitation. In these lectures, I will first recall the relations between the constants, the tests of the local position invariance and of the universality of free fall. I will also detail the main theoretical frameworks in which the low-energy constants may actually be varying, focusing on the unification mechanisms and the relations between the variation of different constants. Many experimental and observational constraints have been obtained from atomic clocks, the Oklo phenomenon, Solar system observations, meteorite dating, quasar absorption spectra, stellar physics, pulsar timing, the cosmic microwave background and big bang nucleosynthesis. I will describe these systems and summarize the constraints obtained. I will also discuss the need for a cosmological model to compare these observations.
Where: Université de Genève, Ecole de physique, 24, quai Ernest-Ansermet, Auditoire Stückelberg