Schwinger-type boson realization for the su(4) algebra - In relation to the description of many-fermion systems in pairing correlation

Considering the present situation of Lie-algebraic studies of high-temperat ure superconductivity, a Schwinger-type boson realization of the su(4) alge bra is investigated. The basic framework comes from a possible form of the su(n) and the su(n, 1) algebras in the Schwinger representation, which was recently proposed by two of the present authors (M. Y. & A. K.), together w ith J. da Providencia. The form investigated in this paper is, in some sens e, a natural extension of the Schwinger boson representation for the so(5), so(4) and su(2) x su(2) algebras, which was also proposed by the present a uthors. The orthogonal set for the irreducible representation of the su(4) algebra is completely analogous to that expressed in terms of fermion opera tors for pairing correlation.