Spin doctor of another nature

A simulation shows the presence of two prominent vortices, shown in blue, that spontaneously appear in a condensate, shown in red, with other smaller vortices near the boundary of the BEC. The area below the three-dimensional rendering shows what an image of this BEC might look like in an actual experiment, where a laser beam, the white region, shines on a BEC, and the BEC casts a shadow, the dark region, with two bright spots indicating the two main vortices. The grayscale here is reversed from the grayscale used to show the actual experimental images. (Credit: University of Queensland/Chris Foster)

Physicists from UQ's School of Physical Sciences have produced simulations of a strange phenomenon known as spontaneous quantum vortices.

Dr Matthew Davis and Dr Ashton Bradley have successfully modelled experiments on the formation of BECs recently conducted in the lab of Associate Professor Brian Anderson and co-workers at The University of Arizona.

The experimental and computational results have been published in the prestigious Nature journal.

“We have used a relatively new computational method to describe these systems and found our simulations to be in agreement with the lab measurements. It has given us an insight into the microscopic physics that could not be observed in the experiment,” Dr Davis said.

A BEC forms when a gas of identical particles is cooled to temperatures a few billionths of a degree above absolute zero. At this temperature they lose their identity and start to behave as a single entity.

A BEC consists of up to a million atoms and is the matter equivalent of laser light. It exhibits a property known as superfluidity, whereby atoms can flow across rough surfaces without ever slowing down.

A quantum vortex is another manifestation of superfluidity where the entire BEC begins to spin, creating a mini-tornado of atoms with no particles in the eye of the storm.

Dr Matthew Davis and Dr Ashton Bradley are members of The University of Queensland node of the Australian Research Council Centre of Excellence for Quantum-Atom Optics.

The Centre focuses on fundamental research, but their long-term goal is to underpin and develop the next generation of quantum technology.

Media: Dr Matthew Davis (07 3346 9824) or Lynelle Ross, School Communication and Marketing Officer (07 3346 9935).