G. Dattoli et al., BIORTHOGONAL BASES FOR COUPLED HARMONIC-OSCILLATORS, Nuovo cimento della Societa italiana di fisica. B, Relativity, classical and statistical physics, 111(12), 1996, pp. 1529-1534
We show that a generalized class of harmonic-oscillator wave functions
can be exploited in order to study physical problems involving couple
d harmonic oscillators. We further discuss the biorthogonal properties
of these states, the relevant creation and annihilation operators and
some physical consequences of the formalism.