Séminaire

Cosmological correlators encode the signatures of the universe's evolution, and by measuring correlations in the late universe we infer the dynamics and contents of the universe. I will review some recent developments in the study of the structure of quantum field theory in curved spacetimes, and the computation of cosmological correlators.

The Alpha Magnetic Spectrometer (AMS) is a general purpose high energy particle detector, which was successfully deployed on the International Space Station on May 19, 2011. It conducts a unique, long-duration mission of fundamental physics research in space. To date, the detector has collected over 255 billion cosmic ray events. This talk presents the latest AMS measurements of cosmic ray elementary particles. The latest results up to the energies of few Tera-electronvolts reveal distinctive properties of particle fluxes and indicate the existence of a primary source of high-energy electrons and positrons, associated with either Dark Matter or an Astrophysical origin. AMS is poised to continue its mission through 2030, providing unique insights into the origins of cosmic ray matter and antimatter and exploring new physics phenomena within the cosmos.

The experimental quest to extract the full information content of the anisotropies of the Cosmic Microwave Background (CMB) has lead to a Moore's Law-like evolution in instrument capabilities. In this seminar, I explore adapting the technologies developed for the CMB to two other, more challenging science goals: Spectral Distortions, and Intensity Mapping.   I will discuss these science topics and present concepts for instruments that could make precise measurements of these signals. I present the SPECTER instrument concept.

DESI is the first new generation galaxy survey to take data with the goal to shed light on the mechanism that drives the acceleration of the cosmic expansion. We postulate the existence of a mysterious component, dark energy, responsible for such acceleration, and we assume, in our current cosmological model, that dark energy takes the form of a cosmological constant Lambda.

The QCD axion, a fascinating hypothetical particle proposed about 50 years ago, might hold the key to explaining one of the universe’s lingering mysteries: why strong interactions don't seem to break CP symmetry. Perhaps more importantly, it remains one of the most exciting dark matter candidates. 

What would we give to see an even younger image of the Universe from relics of the Big Bang?  And how can one even imagine how to do that?  One of the most subtle and important discoveries in elementary particle physics was to find that the tiny neutral particles that Enrico Fermi called the neutrinos have mass.  This mass was discovered indirectly through an effect predicted by Bruno Pontecorvo, now probed to high precision by KM3Net.