Ultracold Atom Reservoir...

The ultracold atom reservoir. The 3D MOT is located in the centre of the region of cross-hatched copper pipes at the bottom left of the L-shape. Atoms are then guided to the right along the middle pipe in the trio of pipes, which dips into the differential pumping stage (in the U-bend) before rising upwards. The reservoir of ultracold atoms is at the centre of the region of cross-hatched copper pipes at the top of the L-shape. (Courtesy: Jan Mahnke)

Topics: Bose-Einstein Condensate, Condensed Matter Physics, Lasers, Quantum Mechanics, Thermodynamics

A reservoir of ultracold atoms that is topped-up continuously has been unveiled by physicists in Germany and Denmark. The system can store 38 million rubidium atoms at a temperature of 102 μK, and the team says that it could be adapted to work for a wide range of particles and trapping methods. Applications of the reservoir include using the cold atoms in metrology systems or to cool other gases or even tiny objects.

Gases of ultracold atoms and molecules are used in a wide range of applications, including atomic clocks and simulating quantum effects in solid materials. While physicists have come a long way in developing and perfecting techniques for cooling gases to temperatures as low as 50 pK, these are "one-shot" systems in which the gas is cooled in isolation and then the atoms are put to use until their numbers are exhausted or the gas is destroyed by making a measurement. In some cases, however, it would be useful to maintain a continuous reservoir of ultracold atoms that could be used to perform continuous metrology or to cool other systems.

Now, Jan Mahnke and colleagues at Leibniz Universität Hannover and Aarhus Universitet have created a continuously pumped reservoir of ultracold atoms that is integrated within an L-shaped device that is made from a copper block measuring several centimetres across (see image above). The cooling process begins in a separate device that functions as a 2D magneto-optical trap (MOT). This uses laser beams and magnetic fields to cool and guide about 10 billion rubidium-87 atoms at temperatures as low as 25 μK. Some of these atoms are then transferred to the first stage of the reservoir device, which is a 3D MOT that can store about 2 billion atoms.

Physics World: Reservoir of ultracold atoms is filled continuously, Hamish Johnston