Research interests in our research group

Our group mainly works in the interphase between particle physics and cosmology. Our research topics include the dark matter and dark energy problems and baryogenesis problem, cosmic inflation and inhomogeneous cosmologies. Group currently consists of two permanent staff members, one postdoctoral researcher and five PhD-students.Our group mainly works in the interphase between particle physics and cosmology. Our research topics include dark matter, dark energy, baryogenesis, cosmic inflation and inhomogeneous cosmologies. Group currently consists of two permanent staff members, one postdoctoral researcher and five PhD-students.

Seminars and Visitors Schedule

We regularly host international researchers visiting our cosmology group. Our canonical slot for cosmology seminars is Tuesdays at 13:00. We also have regular weekly meetings to discuss the latest results on our field.

Selected publications in year 2017

1. Electroweak baryogenesis from a dark sector

We present a simple UV-complete model that realises a successful electroweak baryogenesis from dark sector. The dark matter gets a CP asymmetry that is transferred to the standard model through a CP portal interaction coupling DM to tau-leptons and an inert Higgs doublet. The model has promising discovery potential at the LHC, while robustly providing a large enough baryon asymmetry and correct dark matter relic density with reasonable values of the couplings.

2. Postinflationary vacuum instability and Higgs-inflaton couplings

A coupling of Higgs field to inflaton can lead to large resonant fluctuations of the higgs field, and destabilize the electroweak vacuum. We perform a careful numerical analysis of the phenomenon and derive upper bounds on quartic and trilinear interactions between the Higgs and the inflaton. We conclude that there exists a favorable range of the couplings within which the Higgs field is stabilized during both inflation and preheating epochs.

3. Do metric fluctuations affect the dynamics of Higgs during inflation?

We verify explicitly that metric fluctuations have a negligible effect on vacuum stability during inflation if the Higgs is energetically subdominant. For Standard Model parameters we find that couplings between the Higgs and metric fluctuations are suppressed at least by a factor 10^(-7). This confirms the validity of previous stability conditions derived by treating the Higgs as a test field in a fixed gravitational background.