When the magnetic trap is turned off, the superatom falls out of it like a drop of liquid (although it's actually still a gas). Importantly, though, this drop is a wave. It can splash and splatter, but it can also be reflected, refracted, phase-shifted, and focused. The smallest superatom is about 1 micrometer across—10 000 times the diameter of a hydrogen atom—and contains anywhere from 100 to 1000 atoms. The largest ones to date are perhaps half a millimeter in size, with maybe 10 million atoms inside them. They persist for tens of seconds before the heat and chaos of the world tear them apart.

To keep the condensate coming, scientists have found ways to move the stuff out of the production chamber to a reservoir so that they can produce a second batch, and a third. The condensate is conveyed through a waveguide formed by laser light.

The material shares exactly one set of quantum mechanical properties, so it can form a beam whose waves march in step. Ketterle and his colleagues were the first to demonstrate this phenomenon by extracting atoms from a sodium condensate in 1997. This first atom laser was comparable to its optical counterpart but had a lower energy output and a far sparser stream of particles—about a trillionth of the photon output of an optical laser. However, the atoms had a wavelength of about 0.1 nm, versus visible light's wavelength of about 400 to 750 nm.

Apart from supersensitive accelerometers, what other applications for atom lasers are in the works? For starters, if you put an accelerometer into a spin (or just send the atom beam around a circuit), you'll have a gyroscope. Three such gyroscopes will tell you how an aircraft moves along all its axes and, just as important, how it rotates around them. You could figure out which way you are now pointing—something the Global Positioning System cannot tell you.

This system of inertial guidance, a kind of dead-reckoning system, works with the help of a little calculus. You measure the acceleration and rotation rates and then go backward, integrating acceleration twice to get the position and integrating the rotation rate once to get the aircraft's rotation. Do this again and again, and you can draw one vector on the tip of another to plot your progress—all without reference to external phenomena.

The problem with using optical lasers in inertial-guidance systems is the noise in the signal. That noise gets integrated, too, and because integration involves an exponent, the errors compound at a fearsome rate. Even the best military inertial-guidance systems now stay accurate for only a few hours; after that, they will calmly inform you that your airplane is tunneling underground or traveling faster than light.

If you could replace the optical laser with an atom laser, however, the system could in principle stay accurate for years at a time. Thanks to the exponent, wavelengths one-70 000th the length of an optical laser's would yield a signal-to-noise ratio 100 billion times as big. That's why the U.S. Navy is funding work at JILA to build a version that is small and sturdy enough for use in a submarine.

The process of miniaturizing the atom laser—which at present can occupy anywhere from a tabletop to an entire lab filled with vacuum and laser equipment—is well under way, in part because many of the tools have already been developed. For instance, engineers already know how to use electrical fields to control atom beams for the epitaxial deposition of atoms on wafers. Jakob Reichel's Microtrap Group at the Max Planck Institute of Quantum Optics, in Garching, Germany, and at the ecole Normale Superieure, in Paris, was the first to successfully make and move around condensates on a chip, using microscopic magnetic traps to cool and manipulate the atoms.

Other groups are also pursuing these "atom chips," which right now are ungainly, lab-built devices. The chips themselves can fit in the palm of your hand, and the vacuum equipment is not much larger. But when you add in the lasers, the whole setup fills the volume of a few desktop PCs.

Even so, while atom chips cannot yet be commercially manufactured, they're proof that such products are feasible. And when an atom-laser gyroscope can finally fit inside a cellphone, children will ask, "Daddy, how did you ever find your way around when all you had was GPS?"