SEMINAR ANNOUNCEMENT:“Bose Polaron in the strongly interacting Regime"

Luis A. Peña Ardila

Aarhus university

“Bose Polaron in the strongly interacting Regime"

An impurity immersed in a Bose-Einstein condensate gets dressed by the low-energy excitations of the quantum gas and forms a quasiparticle termed Bose polaron. In the weakly interacting regime, where the impurity-boson coupling strength is small, many theoretical tools including mean-field and perturbative methods describe very well the physics of the Bose Polaron. However, the strong interacting limit where the impurity-boson scattering length is much larger than the inter-particle distance is still in debate. In this talk I address the ground-state properties of the Bose polaron in the strongly interacting limit. I will show that, more sophisticated techniques such as Monte-Carlo methods (QMC) are needed to describe this regime where quantum fluctuations and quantum correlations play an important role. We compare our findings with the most recent experiments in Aarhus and JILA. In the absence of Efimov physics, we also study the universality of the Bose polaron as a function of the gas parameter na³ of the BEC. Being n the density of the Bose and a the boson-boson scattering length. This equation of state allow us to understand the whether the Bose polaron survives when the bosonic bath is switched adiabatically off.