Bose–Einstein condensates in microgravity

Abstract

We report the current status of our cooperative effort to realize a 87Rb Bose–Einstein condensate in microgravity. Targeting the long-term goal of studying cold quantum gases on a space platform, we currently focus on the implementation of an experiment at the ZARM drop tower in Bremen. Fulfilling the technical requirements for operation in this facility, the complete experimental setup will fit in a volume of less than 1 m3 with a total mass below 150 kg and a total power consumption of the order of 625 W. The individual parts of the setup, in particular the ultra-compact laser system as a critical component, are presented. In addition, we discuss a first demonstration of the mechanical and frequency control stability of the laser modules. On the theoretical side, we outline the non-relativistic description of a freely falling many-particle system in the rotating frame of the Earth. In particular, we show that the time evolution of a harmonically trapped, collisionally interacting degenerate gas of bosons or fermions is as simple in an accelerated, rotating frame of reference as in an inertial frame. By adopting a co-moving generalized Galilean frame, we can eliminate inertial forces and torques. This leads to important simplifications for numerical simulation of the experiment.