Bose-Fermi pair formation in the mixture of cold atomic gases

We study the role of the Bose-Fermi (BF) pair correlations in the cold BF-mixture of atomic gases. After summarizing the previous results on the formation of composite BF-pairs in the uniform BF mixture, we present an exactly solvable model where bosons and fermions are distributed over finite number of orbits and interact via attractive pairing-type interaction. We show that, as the interaction strength increases, BF pairs with different quantum numbers are gradually created in the ground state through a series of level crossings, until finally the system becomes a Fermi sea of BF-pairs.