Coherent mesoscopic quantum tunneling in boson-fermion mixtures

We show that cold atom systems of simultaneously trapped Bose-Einstein condensates (BECs) and quantum degenerate fermionic atoms provide promising laboratories for the study of macroscopic quantum tunneling. Our theoretical studies reveal that the spatial extent of a small trapped BEC immersed in a Fermi sea can tunnel and coherently oscillate between the values of the separated and mixed configurations (the phases of the phase separation transition of BEC-fermion systems). We evaluate the period, amplitude, and dissipation rate for Na-23 and K-40 atoms, and we discuss the experimental prospects for observing this phenomenon.