Edge states of photon pairs in cavity arrays with spatially modulated nonlinearity

Abstract

We study theoretically an extended Bose-Hubbard model with the spatially modulated interaction strength, describing a one-dimensional array of tunneling-coupled nonlinear cavities. It is demonstrated that the spatial modulation of the nonlinearity induces bound two-photon edge states. The formation of these edge states has been understood analytically in terms of nonlinear self-localization. Our results show that the number of excitations and the modulation period of the interaction affect the photonic quantum walks in the universal way and both promote the edge states. Show more