Wacky Firework Effect Created in Special Quantum Gas

By Ryan F. Mandelbaum on at

If you’re into physics making your brain leak out of your ears, you should familiarise yourself with Bose-Einstein condensates. These strange arrangements of atoms can be all the states of matter at once, can look like they have negative mass, and essentially bring the weirdness of quantum mechanics to larger scales.

That means physicists sometimes observe strange new effects in these wacky materials. Most recently, one team observed that, under the right conditions, they could cause a Bose-Einstein Condensate to emit a burst of jets like microscopic fireworks. Check it out:

Image: Cheng et al, Nature (2017)

But what’s going on here? First, the researchers trap and cool caesium atoms in a disk less than ten micrometres in radius with a pair of lasers—this is the Bose-Einstein condensate. Then they put the whole thing in an oscillating magnetic field. After a few milliseconds, bursts of atoms fly out of the system in jets that resemble fireworks. The modulation is what causes the outburst instead of, say, a halo of matter, explained University of Chicago physicist and author Cheng Chin. They published the work yesterday in Nature.

The Bose-Einstein condensate’s secret is that certain particles called bosons can, unlike electrons, occupy the same lowest-energy states. From this falls the observation that large collections of atoms begin to show and amplify effects usually only observed in single particles. But adding the modulating field means the particles are no longer only in the ground state, explained Chin.

These bosons then prefer to bunch together when they’re forced out of the disk. But what does that mean? “We try to argue...that the pattern we see is the amplification of quantum fluctuations,” said Chin. Perhaps the experiment is magnifying the quantum world, and the structure of the fireworks can shed light on what’s truly going on in a vacuum.

...Perhaps. Welcome to the quantum universe. [Nature via University of Chicago]