Onset time for energy oscillations in a two-dimensional trapped Bose gas excited by a red laser potential

TL;DR

This paper investigates the onset of energy oscillations in a 2D trapped Bose-Einstein condensate excited by a moving laser potential, revealing velocity-dependent delay times and universal relations for different excitation depths.

Contribution

It introduces a detailed analysis of energy oscillation onset times in a 2D BEC under laser excitation, highlighting universal behaviors and the impact of potential depth on dynamics.

Findings

Energy oscillations start immediately for velocities below critical.

Delay in oscillation onset depends on laser velocity and potential depth.

For splitting potentials, onset time matches the BEC fragment's travel time to the wall.

Abstract

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.