Gilles Buldgen

PhD student
Funding: FNRS - FRIA


Centre for Cosmology, Particle Physics and Phenomenology - CP3
Université catholique de Louvain
2, Chemin du Cyclotron - Box L7.01.05
B-1348 Louvain-la-Neuve


UCL member card
Research statement
I am interested in the particle physics of the early Universe and its application to cosmology. I also have a genuine interest in finite temperature and nonequilibrium quantum field theory (QFT).

In my PhD project I study quantum and dissipative effects in the early Universe from first principles of nonequilibrium quantum field theory. A key application is the question whether “Warm Inflation” is a viable alternative to the standard inflationary paradigm in cosmology. While the universe is empty and cold in the standard scenario, Warm Inflation is characterised by a quasi-equilibrium between the particle production due to dissipation and the dilution due to the Hubble expansion, which keeps a thermal bath of radiation at constant temperature during inflation. In this scenario, thermal damping helps to maintain the slow rolling of the inflaton field, and thermal fluctuations contribute to cosmological perturbations. The question whether Warm Inflation is feasible is interesting from a particle physics viewpoint because it has been claimed that this scenario can alleviate some of the difficulties that one faces when trying to embed conventional models of inflation into theories of particle physics. It is even more interesting from a cosmological viewpoint because it would radically change our view on the origin of the small density perturbations that formed the seeds for galaxies formations: Those perturbations are purely quantum in conventional models of inflation, while they are both quantum and thermal in the Warm Inflation case. Also the transition from the inflationary period to the radiation era is rather different from the standard scenario because there is no distinct “reheating period” after inflation, the transition to the radiation domination occurs smoothly.
Publications in CP3
All my publications on Inspire