Dates: 6, 13, 20 et 27 june 2013 (14.15pm to 18pm)

Intervenant: Dr. Anthony CHALLINOR, University of Cambridge. 

Description: The course will provide an introduction to the theory behind the anisotropies and polarization of the cosmic microwave background (CMB) radiation, one of the cleanest and most important probes in modern observational cosmology. As the first cosmological results from the ESA Planck CMB satellite will be released in early 2013, the lectures will cover in some depth the topics relevant for understanding the Planck results, and we will also discuss the main findings of the Planck satellite and their implications for cosmology and our understanding of the origin and evolution of the universe.

Dates: March 31st - April 3rd 2014

Organiser: Daniel Figueroa (daniel.figueroa@unige.ch)

Intervenants: Benjamin Audren, Julien Lesgourgues, Thomas Tram

Description:  The course notes are attached at the end of the page.

Schedule: Every day (31.03-3.04) from 10.00 am to 16.15 pm

Where: 

         Monday 31st: Salle 102, Sciences I (1st floor), 

         Tuesday 1st: Salle MaNEP, Ecole de physique

         Wednesday 2nd: Salle Datcha, near Nathalie Chaduiron office

         Thusday 1st: Salle MaNEP, Ecole de physique

Dates: 16, 23, 30 october and 6 november 2014 (14.15pm to 18pm)

Intervenant: Dr Jens CHLUBA, Associate Research Scientist, Johns Hopkins University. 

Description: It was already realized in the early days of CMB cosmology that tiny deviations of the cosmic microwave background (CMB) spectrum from a blackbody -- commonly referred to as spectral distortions -- provide a powerful tool for studying the thermal history of our Universe. Since COBE/FIRAS, we know that the average CMB spectrum is extremely close to a perfect blackbody, with deviations limited to one part in ten thousand. Some quarter-century has past since then and technological advances in principle allow improving current constraints on the CMB spectrum by more than three orders of magnitude. In addition, there are several processes in the the early Universe that should create spectral distortions within reach of this new technology. It is thus time to return our attention to the physics of CMB spectral distortions and ask how and what can we learn by studying them. In these lectures, the physics going into the formation and evolution of CMB spectral distortions in the early Universe will be covered. We will start from the Boltzmann equations describing the basic interaction between photons and matter (Compton, double Compton and Bremsstrahlung) and discuss simple analytic solutions of the problem in the pre-recombination era. Particular attention will be given to the different types of distortions (mu, y and residual distortion) and methods for computing them efficiently. We will cover various energy release scenarios (e.g., decaying and annihilating particles), highlighting in particular the physics of the damping of small-scale acoustic modes and possible constraints on the primordial power spectrum. We will then move through the recombination era, highlighting the spectral features associated with hydrogen and helium as one of the important new probes of the epoch. In the post-recombination era, structures form and heat the medium, creating y-distortions at different scales. We will highlight the physics of Sunyaev-Zeldovich effect how we can learn about cluster ’gastrophysics’ and cosmology from this.

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