Théorie

Astronomie multi-messagere

La découverte des ondes gravitationnelles et des source(s) astrophysiques des neutrinos de hautes énergies ont marqué le début d’un nouveau type d'astronomie, "astronomie multi-messagère". L'idée de l'approche multi-messagère est de combiner les signaux électromagnétiques (radio, visible, rayons X et gamma) provenant des sources astronomiques avec des signaux neutrino et/ou des ondes gravitationnelles pour établir la nature des phénomènes physiques ayant lieu dans les sources comme les trous noirs et les étoiles à neutrons. 

Astronomie multi-messager

La découverte des ondes gravitationnelles et des source(s) astrophysiques des neutrinos de hautes énergies ont marqué le début d’un nouveau type d'astronomie, "astronomie multi-messagère". L'idée de l'approche multi-messagère est de combiner les signaux électromagnétiques (radio, visible, rayons X et gamma) provenant des sources astronomiques avec des signaux neutrino et/ou des ondes gravitationnelles pour établir la nature des phénomènes physiques ayant lieu dans les sources comme les trous noirs et les étoiles à neutrons. 

Astronomy at the highest energy frontier

Astronomical sources are observed nowadays across different domains of electromagnetic spectrum (from radio to gamma-rays) and different astronomical "messengers" (photons, neutrinos, gravitational waves). Combining different types of observational data we have learned that some types of sources operate huge high-energy particle accelerators / colliders boosting particle energies to ten million times higher energies than reached at the Large Hadron Collider at CERN. 

Using the AdS/CFT correspondence to study phases of gauge theories, at strong coupling at finite temperature and density.

The AdS/CFT correspondence give a new perspective both at strong coupling physics of quantum field theory and the nature of the gravitational interaction. This thesis will deal with analysing the physics of gauge theories at finite temperature and density, their phase diagrams and their consequences for the physics of neutron stars, strange stars,  black holes,  cosmological fluids and strange metals.

Constraining the early Universe with primordial black holes

Scientific context

Cosmological inflation is a period of accelerated expansion that occurred at very high energy in the early Universe. During this epoch, vacuum quantum fluctuations were amplified to become large-scale cosmological perturbations that seeded the cosmic microwave background (CMB) anisotropies and the large-scale structure of our Universe.

Gamma-ray astronomy with axion-like particles and search for intergalactic magnetic fields

The future gamma-ray experiment CTA plans to measure the fluxes of blazars in the energy range from 30 GeV to 100 TeV with sensitivity 10 times superior to present measurements. Intergalactic magnetic fields can be measured through observations of the secondary photons through time delay in blazar flairs, signatures in spectra and extended emission around the point sources.

Neutrinos, neutrino properties and dense astrophysical environments

A major progress has been made in neutrino physics after the discovery of the neutrino oscillations. Crucial questions are being addressed experimentally and should receive an answer soon, including the absolute neutrino mass and mass ordering, the existence of sterile neutrinos and of CP violation in the lepton sector. Intriguing open issues also concern how neutrinos modify their flavor in astrophysical environments.

Théorie