Dynamical instability of a two component Bose-Einstein Condensate in an optical lattice

Abstract

We investigate the dynamical instability for a two component Bose-Einstein Condensate (BEC) in an optical lattice. We assume that the two components are in sinusoidal potentials with the same period but different phases. We find a swallow-tail type instability near the band edge, however an extra tail is formed due to the inter-component interaction. Depending on the phase difference of the potentials, the instability region may expand or shrink with increasing inter-component interaction.