Exact eigenstates for a class of models describing multiphoton processes in the presence of seven bosonic modes.

We present the analytical expressions of eigenstates and eigenenergies by using a parameter λ without the assumption of Bethe anzatz for three kinds of seven-bosonic-mode mixing models. The parameter is shown to be, determined by the roots of a simple polynomial. We also demonstrate the exact analytical expressions of eigenstates and energies without any unknown parameter. [ABSTRACT FROM AUTHOR]