Dynamical classical superfluid-insulator transition in a Bose-Einstein condensate on an optical lattice

Abstract

We predict a dynamical classical superfluid-insulator transition in a Bose-Einstein condensate (BEC) trapped in a combined optical and axially-symmetric harmonic potentials initiated by a periodic modulation of the radial trapping potential. The transition is marked by a loss of phase coherence in the BEC and a subsequent destruction of the interference pattern upon free expansion. For a weak modulation of the radial potential the phase coherence is maintained. For a stronger modulation and a longer time of holding in the modulated trap, the phase coherence is destroyed signaling a classical superfluid-insulator transition. The results are illustrated by a complete numerical solution of the axially-symmetric mean-field Gross-Pitaevskii equation for a repulsive BEC. Suggestion for future experiment is made.