Onset time for energy oscillations in a two-dimensional trapped Bose gas   excited by a red laser potential
  We explore the energy dynamics of a two dimensional (2D) harmonically trapped Bose-Einstein condensate inside a box potential, excited by a moving red-detuned laser potential (RDLP). For an RDLP velocity $v$ less than a critical value $v_c$, energy oscillations are observed to begin simultaneously with the motion of the RDLP. For $v > v_c$, these oscillations are delayed through a transient in the energy. At the end of the delay time $t_{ons}$, the energy oscillations are regenerated again, and $t_{ons}$ is found to depend on $v$ through universal relations for two cases: one for an RDLP depth sufficient to break off a BEC fragment, another for a depth insufficient to split the BEC. In the case of splitting, $t_{ons}$ exactly equals the time it takes the BEC fragment (dragged by the RDLP trough) to reach the hard wall of the box potential. 
Roger R. Sakhel and Asaad R. Sakhel
cond-mat.quant-gas