Prospects for Measurements of Spectral Distortions and Intensity Mapping

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.

f(R) Gravity in an Ellipsoidal Universe

Probing the nature of dark energy with DESI DR2

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.

Speed of Gravity and Cosmology Constraints from Binary Neutron Stars using Time Delays between Gravitational Waves and Short Gamma-ray Bursts

The landmark detection of a gravitational wave (GW) from the Binary Neutron Star Merger (BNS) GW170817 and its electromagnetic counterparts allowed us to study the Universe in an entirely new way. Among the several discoveries made possible by GW170817, we can find the tightest constraints on the speed of gravity and the measurement of the Hubble constant (H0). Both of these measurements were made thanks to several assumptions and conditions that might not hold for future detections.

Axion Condensation Inside Neutron Stars

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.

How to unravel early moments of the Universe with neutrinos: introduction to the PTOLEMY project

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.

Hot and dense perturbative QCD in a very strong magnetic background

Theory journal club

Discussion of the paper

Love numbers beyond GR from the modified Teukolsky equation
Pablo A. Cano
https://arxiv.org/pdf/2502.20185

Neutrino-Nucelus Interaction Physics in 1-10 GeV

Precise nuclear physics theories and models are playing an increasingly important role in neutrino physics. While this has long been recognized in low-energy neutrino experiments, recent advances in accelerator-based neutrino oscillation studies have further highlighted the importance of nuclear many-body effects. Modern experiments such as T2K and NOvA require accurate simulations of nucleon correlations, a necessity that will persist in future experiments like ORCA and IceCube-Upgrade, DUNE, and Hyper-Kamiokande.

Backreaction and Cosmic Butterflies: what simulations can tell us about inflation

The small-scale physics of inflation can leave unique observational signatures in the gravitational wave background and may also generate primordial black holes as a dark matter candidate. These phenomena often involve a significant enhancement of inflationary fluctuations, potentially leading to the breakdown of standard perturbation theory. In this talk, I will discuss how lattice simulations provide a crucial tool for addressing these challenges.

LABORATOIRE

ASTROPARTICULE & COSMOLOGIE

Séminaire