Coherent control of cold atoms and Bose-Einstein condensates by light

Chris J. Vale

Ultra-cold atoms and Bose-Einstein condensates (BECs) provide a dramatic example of a quantum system on a macroscopic scale. Atoms can be cooled down to temperatures below 1μK and their de Broglie wavelengths become large enough to be readily observed in experiments. This has spawned a new research area known as atom optics which refers to the study and control of atoms based on their wave nature. In recent years, physicists have been performing experiments with coherent atoms from a Bose-Einstein condensate. The ability to produce and manipulate condensates above microfabricated surfaces may one day lead to new technologies such as atom interferometers on a chip.

Benjamin P. Holder

D. Naik

Since Feynman's realization of using quantum systems to investigate quantum dynamics, interest in creating controllable quantum systems to simulate condensed matter phenomenon has been high. With the realization of BECs in 1995, the realization of a relatively clean testbed for simulating some of these phenomenon became a reality. \n My PhD research has been an exploration of the production and use of Bose-Einstein Condensates for the study of superfluidity. The first 3 years have been spent in the actual building of a Na BEC apparatus. During this time, we’ve implemented a distinct technique to trap ultra cold Na atoms, i.e. the Optically Plugged Trap. In the process, we have shown how atoms in a linear trap can show spin metastability and thus maintain a nonequilibrium state for long periods of time.\n In studying the interaction of ultra-cold atoms with light, we have developed a technique to measure the velocity distribution of atoms using a standing optical wave (Bragg Spectroscopy). Alongside this, we have also created optical traps for atoms in which we can change to shape of the trap itself to probe different condensed matter systems. The eventual goal being the investigation of condensed matter physics, specifically superfluidity, using ultra-cold atoms.

Kristian Helmerson

A. Kasper, Sophie Schneider, Ch. vom Hagen +7 more

We describe an experiment to create a sizable 87 Rb Bose–Einstein condensate (BEC) in a simple magnetic microtrap, created by a current through a Z-shaped wire and a homogeneous bias field. The BEC is created close to a reflecting surface. It is an ideal coherent source for experiments with cold atoms close to surfaces, be it small-volume microtraps or directly studying the interactions between cold atoms and a warm surface.

Heping Zeng, Fucheng Lin, Weiping Zhang