Théorie

Dissipative phenomena are ubiquitous in physics, arising in systems across a vast range of energy scales, from condensed matter and fluid dynamics to astrophysics and cosmology. While traditional effective field theory (EFT) methods have been remarkably successful in describing isolated systems, many physically relevant systems involve interactions with environments that induce dissipation, noise, and non-conservative dynamics. Extending EFT techniques to such open systems has become an active and rapidly developing area of research. This thesis is devoted to the study of gravitational systems with dissipation and their field-theoretic description. In particular, it focuses on the following topics: an effective field theory description of dissipative effects in self-gravitating compact objects and their connection to gravitational-wave observations; models with dissipative dynamics in the evolution of the early and late-time universe in cosmology.

The origin of PeV Galactic cosmic rays is still unknown and challenged by recent LHAASO gamma-ray and IceCube neutrino observations. This PhD project aims to develop a new cosmic-ray propagation code that models transient PeVatron sources and realistic particle transport in the Galactic magnetic field. By comparing theoretical predictions with current and future gamma-ray and neutrino data, the project will constrain the nature of Galactic PeVatrons and cosmic-ray propagation at the highest energies.

The research project  will focus on applications of the holographic gauge/gravity duality to the description of the dense state of strongly interacting  matter, and in particular to static and dynamical properties of neutron stars.