Tunnelling couplings in discrete lattices, single particle band structure and eigenstates of interacting atom pairs

Abstract

By adjusting the tunnelling couplings over longer than nearest neighbor distances it is possible in discrete lattice models to reproduce the properties of the lowest energy band of a real, continuous periodic potential. We propose to include such terms in problems with interacting particles and we show that they have significant consequences for scattering and bound states of atom pairs in periodic potentials.