Large N expansion for strongly-coupled boson-fermion mixtures

► Large N boson-fermion mixture is rewritten by composite fermions with 1/N expansion. ► The 1/N expansion is equivalent to the loop expansion of composite fermions. ► The leading-order study yields a free gas of composite fermions at low energies. ► The next-to-leading term gives a weak attraction between composite fermions. ► Up to the next-to-leading order there can be the superfluidity of composite fermions.