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.
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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.
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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
