Bound States of a System of Two Fermions on Invariant Subspace

We consider a Hamiltonian of a system of two fermions on a three-dimensional lattice Z3 with special potential . The corresponding Shrödinger operator H(k) of the system has an invariant subspac L-123(T3) , where we study the eigenvalues and eigenfunctions of its restriction H-123(k). Moreover, there are shown that H-123(k1, k2, π) has also infinitely many invariant subspaces , where the eigenvalues and eigenfunctions of eigenvalue problem are explicitly found.