Loss of coherence and superfluid depletion in an optical quasicrystal

We study numerically a 2D Bose–Einstein condensate in a quasiperiodic array of potential peaks, assumed to be generated by superimposing five blue detuned laser beams. By using a Bogoliubov ansatz we show that the system experiences a loss of coherence and starts developing a normal part. We give estimates where a phase transition to an insulating phase should happen for the use of future experiments, along with a study of the validity of the Bogoliubov approximation. (paper)