A Nano-Electron-Volt Neutral Atom Storage Ring

A nano-electron-volt neutral atom storage ring, built and tested by physicists at Georgia Tech, should help the development of atom fiber optics.

Generally, storage rings not only store particles but also serve to define an energy and trajectory insofar as the particles are guided around a prescribed track by some kind of magnet system; particles with the wrong energy would fly away. Normally the magnets exert themselves by grabbing onto the particles' electric charge. Neutral atoms don't have a net charge but they can possess a net dipole moment which, if the atom is moving slowly enough, is sufficient for guidance (see figure).

The Georgia Tech experiment (Michael Chapman, michael.chapman@physics.gatech.edu, 404-894-5223, Jacob Sauer, jakesauer@mindspring.com, Murray Barrett, m.barrett@mindspring.com) is much more modest than your typical particle accelerator: it's only 2 cm across and corrals neutral rubidium atoms moving at speeds of 1 meter/sec (equivalent energy=nano-eV, temperature=microkelvins).

So far swarms of one million atoms have made as many as seven circuits around the ring. The same researchers produced the first all-optical generation of a Bose-Einstein condensate (Update 545), and they hope to load the atoms from a condensate with their new storage ring (dubbed the "Nevatron"). Possible goals include ultra-sensitive gyroscopes and atom lasers. (Sauer et al., Physical Review Letters, 31 December 2001; also see group website.)