Unitarily invariant decomposition of arbitrary hermitian matrices of physical interest

The aim of this article is to report a unitarily invariant decomposition of arbitrary Hermitian second-order matrices. For the particular cases of antisymmetrical and symmetrical Hermitian second-order matrices this decomposition reduces to the unitarily invariant decompositions of antisymmetrical and symmetrical Hermitian second-order matrices reported by Coleman, A. J. In: Erdahl, R. M., ed. Reduced Density Operators with Applications to Physical and Chemical Systems II, Queen's Paper in Pure and Applied Mathematics, vol. 40; Queen's University: Kingston, Ontario, 1974 and Sun et al. Int J Quantum Chem 1984, 25, 1045, respectively. An illustration of physical interest is reported. (C) 2003 Wiley Periodicals, Inc.