Atom microchips get off the ground

Electrons have been scooting around microchips, or integrated circuits, since the 1970s.

Now, it’s the atoms’ turn. Physicists using fabrication techniques developed for ordinary microcircuits are creating diminutive devices that direct atom flows.

Atom chips could lead to both more-accurate missiles and more-complex atom-optics experiments (SN: 5/8/99, p. 296), researchers say. The chips might also help usher in ultrafast computers based on quantum mechanics (SN: 11/20/99, p. 334: http://www.sciencenews.org/sn_arc99/11_20_99/bob2.htm.).

Demonstrating the most versatile atom circuit so far, Ron Folman of the University of Innsbruck in Austria and his colleagues have created a device that can both store and guide a cloud of atoms. The team, led by Innsbruck’s Jörg Schmiedmayer, used the smallest wires to date for atom chips, although their 10-micrometer width is not thin by electronics standards.

As described in the May 15 Physical Review Letters, Folman and his coworkers created their chip from gold-coated gallium arsenide. To make wires, they etched away the gold in thin parallel lines to leave conducting strips between the furrows.

After lasers and external magnetic fields cooled and trapped lithium atoms above the chip, the team shut off those influences. Electric currents in the gold wires then took control. They magnetically trapped the hovering atoms in a line and guided them above a wire.

Schmiedmayer says that the device passed another milestone by creating the trapping conditions that theorists have determined are needed for quantum computing. The chip is “impressive,” comments Nynke H. Dekker of Harvard University, but the tougher job of putting all the atoms in a useful trapped state still looms.

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