# Focus: Video—Condensate Duo Puts on a Show

Physics 11, 18
Simulations of the mixing of two oppositely polarized Bose-Einstein condensates produce fingering patterns that look like those of classical fluids.

Computer simulations of the mixing of a pair of Bose-Einstein condensates (atomic gases cooled to their quantum ground states) reveal a “fingering” pattern previously seen only in classical fluids, such as in a lava lamp. A team of theorists produced the simulations as a demonstration of the surprising patterns that can form spontaneously in a quantum system.

The researchers, led by Hiroki Saito of the University of Electro-Communications in Tokyo, simulated two condensates whose atoms are the same except that they have magnetic dipole moments (internal “bar magnets”) pointing in opposite directions. Initially, magnetic interactions are turned off, and the condensates are arranged in the pancake-shaped trap with one sitting in a central disk and the other forming a surrounding ring. At the start of the two simulations shown above, the magnetic (dipole) interaction force is suddenly switched on, so that—in the classical view—each atom behaves like a bar magnet that is either aligned or anti-aligned with each of its neighbors. The strength of this interdipole force determines the size of the fingers that appear, as shown by the two videos.

The researchers say that their simulations could be brought to life using chromium atoms and standard manipulations with magnetic fields.

This research is published in Physical Review A.

–David Ehrenstein

David Ehrenstein is the Focus Editor for Physics.

## Subject Areas

Atomic and Molecular Physics

## Related Articles

Atomic and Molecular Physics

### Synopsis: Watching a Molecule Relax While it Reacts

Atomic force microscopy detects the subtle structural changes that take place when a molecule is ionized. Read More »

Atomic and Molecular Physics

### Synopsis: Spectral Evidence of a Supersolid Made of Cold Atoms

Researchers find new evidence that a Bose-Einstein condensate made of erbium atoms undergoes a phase transition into a bizarre form of quantum matter. Read More »

Atomic and Molecular Physics

### Synopsis: Correcting Hardware Bias in Molecular Spectrometers

More accurate measurements of ${\text{CO}}_{2}$ in the atmosphere can be obtained by accounting for discrepancies in spectroscopy hardware. Read More »