Vortices Turn BECs into Gyroscopes

When it comes to building gyroscopes, matter-wave interferometers conquer all. Send a beam of matter around the arms of an interferometer, and you get some 10 orders of magnitude higher sensitivity than with photons.

But there’s a problem. While it’s a simple matter to build mirrors and beam splitters for photons, it’s extremely difficult to do that for matter waves. As a result, matter-wave interferometers are expensive, troublesome machines.

Now Jonathan Dowling at Louisiana State University, in Baton Rouge, and a couple of buddies have come up with a better way of building matter-based gyroscopes that should be smaller, cheaper, and more stable.

The idea is to make the measurement using a Bose-Einstein Condensate, a collection of atoms that has been cooled to a state in which they share the same existence.

BECs have been studied intensively in the 15 years since they were first created. Physicists know, for example, that it is possible to create vortices inside BECs by zapping them with a helical light beam created by passing it through a holographic plate.

The trick that Dowling and co have come up with is to create a superposition of counter-rotating vortices inside a BEC using this technique. This should set up an interference pattern in the density of atoms in the BEC that can be easily measured by photographing it.

And since this pattern should change as the BEC rotates, the system is perfect for gyroscopy.

Dowling and pals calculate that a single BEC gyroscope that measures just a few millimeters square should be almost as sensitive as a matter-wave interferometer that is several square meters in size. By using an array of many BEC gyroscopes, it should be possible to dramatically increase the sensitivity. And since the device requires no matter-wave mirrors or beam splitters, it should be considerably simpler and easier to operate.

That’s a smart idea with considerable potential. The question now is who can build one and how soon.

Ref: arxiv.org/abs/0907.1138: Ultra-Stable Matter-Wave Gyroscopy with Counter-Rotating Vortex Superpositions in Bose-Einstein Condensates