We look into the micro-world of ultracold atoms: our dual-species Bose-Einstein condensates are a few micrometers in size and have a temperature of less than a millionth of degree above absolute zero. We shield these fragile and delicate creatures from the hostile outside world by imprisonment in high-vacuum chambers.
Absorption images of two immiscible K and Rb condensates repelling each other (left column). The density profiles of the two condensates are well described by numerical solutions of the nonlinear Schroedinger equations (right column).
Quantum Mixtures of degenerate atoms are ideal platforms to study and simulate multi-component quantum many-body systems where the mutual interactions are crucial, relevant to diverse fields from condensed matter to astrophysics.
In our lab we produce dual species Bose-Einstein condensates of K and Rb with tunable interspecies interactions. This experimental setting allows the investigation of multi-component superfluidity, quantum magnetism, polaron impurities, miscible/immiscible phase transitions. Furthermore, by properly tuning the interparticle interactions, we access new regimes where quantum fluctuations give rise to the formation of exotic quantum states as self-bound liquid-like droplets, as recently observed in our group.
We also study trapped atom interferometry with single-species Bose-Einstein condensates in multiple momentum components generated by time-dependent optical lattices: in this setting we look for evidence of quantum correlations leading to enhancements of the interferometer sensitivity. Such observations are meant to provide insight on the photon output of quantum-cascade lasers frequency combs.