Surface effects in magnetic microtraps

Abstract

We have investigated Bose-Einstein condensates and ultracold atoms in the vicinity of a surface of a magnetic microtrap. The atoms are prepared along copper conductors at distances to the surface between $300\ensuremath{\mu}\mathrm{m}$ and $20\ensuremath{\mu}\mathrm{m}.$ In this range, the lifetime decreases from 20 s to 0.7 s showing a linear dependence on the distance to the surface. The atoms manifest a weak thermal coupling to the surface, with measured heating rates remaining below 500 nK/s. In addition, we observe a periodic fragmentation of the condensate and thermal clouds when the surface is approached.