Anomalous quantum reflection as a quasidynamical damping effect

We develop a quasianalytical theory for the quantum reflection amplitude of Bose-Einstein condensates. We derive and calculate the decay width of a Bose-Einstein condensate (BEC). A general relation between the time-dependent decay law of the system and its quantum reflection amplitude allows us to explain the quantum reflection anomaly of Bose-Einstein condensates present in BEC-surface systems as a direct consequence of the repulsive particle interaction.

Figure 1

Damping function ${\Gamma }_{\gamma }(\kappa )$ calculated by Eq. (17) for $\gamma =0.5$.

Figure 2

Comparison between numerically obtained decaying densities $\rho (\tau )$ (full lines) and approximated decaying densities $\langle \rho (\tau )\rangle$ (dashed lines) by Eq. (18) for ($\sigma =30,\gamma =0$) above and ($\sigma =30,\gamma =0.5$) below.

Figure 3

Quantum reflection probabilities according to Eq. (19) for ($\sigma =30,\gamma =0.5$) (full line) and ($\sigma =30,\gamma =0$) (dashed line).