Hole motion in a coupled-chain model: some exact results

Abstract

Some exact results on single-hole dynamics in a coupled-chain model are derived. The hole moves in the background of a dimer state which is the exact ground state of the model in the absence of the hole. Three different types of exact eigenfunctions have been determined describing (1) the motion of a bound object of the hole and a free spin 1/2 in a sea of singlets, (2) a state in which the bound object of hole and free spin 1/2 stays close to a localized triplet excitation, and (3) a state in which the bound object moves away from the triplet excitation. The energy eigenvalues corresponding to the three eigenfunctions have been exactly determined.