Effect of loss on the topological features of dimer chains described by the extended Aubry-André-Harper model

摘要

By introducing loss to one sublattice of dimer chains described by the extended Aubry-André or Harper(AAH) model, we study the topological features including the winding number, the edge states, Chern number, and spectrum of the chain. We find that the parameter region for the system to have real band-gap closing is increased due to the loss, and the average displacement of the single excitation can indicate the topological features of the chain in the presence of loss on one sublattice. The robustness of the zero energy eigenstate against four kinds of disorders are examined. A feasible experimental apparatus based on coupled waveguides to observe the predictions of this work is proposed.