B. Huang, I. Fritsche, R. Lous, C. Baroni, J. T. Walraven, E. Kirilov, R. Grimm Breathing Mode of a BEC Repulsively Interacting with a Fermionic Reservoir,
Phys. Rev. A 99 41602 (2019-04-03),
http://dx.doi.org/10.1103/PhysRevA.99.041602 doi:10.1103/PhysRevA.99.041602 (ID: 720106)
We investigate the fundamental breathing mode of a small-sized elongated Bose-Einstein condensate coupled to a large Fermi sea of atoms. Our observations show a dramatic shift of the breathing frequency when the mixture undergoes phase separation at strong interspecies repulsion. We find that the maximum frequency shift in the full phase-separation limit depends essentially on the atom number ratio of the components. We interpret the experimental observations within a model that assumes an adiabatic response of the Fermi sea, or within another model that considers single fermion trajectories for a fully phase-separated mixture. These two complementary models capture the observed features over the full range of interest.