Synopsis: Steps toward a new quantum fluid

Experimenters have created overlapping quantum fluids of lithium and ytterbium, en route to creating quantum fluids of molecules that have unpaired electronic spins.
Synopsis figure
Credit: H. Hara et al., Phys. Rev. Lett. (2011)

Physicists regularly trap and cool atoms with lasers to form quantum fluids such as the Bose-Einstein condensate, but some researchers have recently shifted their attention from atoms to molecules, whose internal complexity could give rise to new phenomena.

One way to do this is to cool pre-existing molecules, and so far, it has been possible to cool a diverse set of molecules, though not yet to both high densities and ultracold temperatures. An alternative method is to first cool overlapping clouds of individual atoms and only then coax them into forming molecules. Using this technique, researchers have created ultracold molecules from weakly bound pairs of different alkali metals, notably potassium and rubidium. But such molecules always contain an even number of spins, so that electrons with opposite spins tend to pair up. Hideaki Hara of Kyoto University and colleagues are instead working to make molecules that combine atoms from different columns of the periodic table, which will contain unpaired spins and should reveal new types of behavior.

As a step towards that goal, the researchers report in Physical Review Letters simultaneously trapping lithium and ytterbium. By weakening the trap to let the most energetic ytterbium atoms evaporate, they cooled the remaining ones to below a microkelvin. Collisions cooled the lithium-6 to the same low temperature, which was one tenth of its Fermi temperature. This degenerate state coexisted, in separate experiments, with either fermionic ytterbium-173 or bosonic ytterbium-174, each of which was also in the quantum regime. – Don Monroe


Features

More Features »

Announcements

More Announcements »

Subject Areas

Atomic and Molecular Physics

Previous Synopsis

Fluid Dynamics

Reluctant swimmers

Read More »

Next Synopsis

Materials Science

X rays scratch the surface

Read More »

Related Articles

Synopsis: Making Mixtures of Magnetic Condensates
Atomic and Molecular Physics

Synopsis: Making Mixtures of Magnetic Condensates

A condensate mixing two species of strongly magnetic atoms provides a new experimental window into many-body phenomena. Read More »

Synopsis: Ion Suppresses Rydberg Creation
Atomic and Molecular Physics

Synopsis: Ion Suppresses Rydberg Creation

Forming an ion in an ultracold atomic cloud delays the subsequent creation of a Rydberg atom until the ion wanders away. Read More »

Viewpoint: Cold Atoms Bear a Quantum Scar
Quantum Information

Viewpoint: Cold Atoms Bear a Quantum Scar

Theorists attribute the unexpectedly slow thermalization of cold atoms seen in recent experiments to an effect called quantum many-body scarring. Read More »

More Articles