Enhanced Quantum Reflection of Ultracold Atoms with Strong Interatomic Interaction

We calculate the reflection probability for ultracold alkali atoms incident on a solid surface. By considering the interatomic interaction and using the WKB method, it is shown that the repulsive interaction between atoms has the effect of increasing the reflection probability. The increasing amplitude is related with the interatomic interaction and the depth of atom-surface potential. In addition, we also perform a numerical calculation to testify the effect of the interatomic interaction, and the analytic result is proven by the numerical result.