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.

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.

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.

The origin of  very high energy astrophysical neutrinos recently discovered by IceCube experiment  at South Pole is still unknown.

L'objectif de la thèse est d'étudier les possibilités d'extensions d'un formalisme permettant de considérer des équations de champs en espace-temps courbes à quatre dimensions à partir d'équations de champs dans l'espace plat R6 Plus précisément il s'agirait d'étudier le possibilité de théories de champs dans R6 muni de la métrique (+,+,-,-,-,-) et leurs restrictions, en particulier, aux espaces de Robertson-Walker. L'intérêt d'un tel formalisme étant la possibilité d'utiliser le cadre a priori plus simple d'un espace plat pour l'étude de champs classiques et quantiques. Les différents résultats obtenus dans ce cadre peuvent donner lieu à des problématiques diverses de théorie des champs ou de formalisme.