Topological transitions of interacting bosons in one-dimensional bichromatic optical lattices (original) (raw)

Ultra-cold atoms in 1D bi-chromatic optical lattices constitute a surprisingly simple system for the study of topological insulators. We show that bosons in 1D bi-chromatic lattices present as a general feature the existence at equal fractional filling of Mott-insulator phases with different topological character. These different phases are a direct consequence of the bosonic and interacting nature of the particles and the topological nature of the Bloch bands. We demonstrate that the associated hidden topological transitions may occur both as a function of the superlattice strength and due to inter-site interactions. We discuss in addition the topological character of incommensurate density wave phases in quasi-periodic superlattices.