How bosonic is a pair of fermions?

A. S. Alexandrov

Morikazu TODA

Aleksej Nikolaevich Storozhenko, Peter Schuck, T. Suzuki +2 more

Propagation of a Boson-Fermion (BF) pair in a BF environment is considered. The possibility of formation of stable strongly correlated BF pairs, embedded in the continuum, is pointed out. The Fermi gas of correlated BF pairs shows a strongly modified Fermi surface. The interaction between like particles is neglected in this exploratory study. Various physical situations where our pairing mechanism could be of importance are invoked.

Morikazu Toda

Jordi Mur-Petit, A. Polls, M. Baldo +1 more

The possibilities of pairing in two-dimensional boson-fermion mixtures are carefully analyzed. It is shown that the boson-induced attraction between two identical fermions dominates the p wave pairing at low density. For a given fermion density, the pairing gap becomes maximal at a certain optimal boson concentration. The conditions for observing pairing in current experiments are discussed.

K. Taniguchi, Y. Miyanishi

We propose a new method that transcribes the fermion system to the boson-fermion system by introducing a unitary operator defined in the whole boson-fermion space. We obtain the boson-fermion expansion of the fermion pair operators such that only the collective pair modes are transformed into boson operators while the non-collective modes are unchanged in the lowest order approximation. The odd- A system is treated in the same formalism as the even-even nuclear system. We briefly discuss the relation between our method and the conventional boson expansion theory.