Physicists at the National Institute of Standards and Technology (NIST) have for the first time linked the quantum properties of two separated ions (electrically charged atoms) by manipulating them with microwaves instead of the usual laser beams, suggesting it may be possible to replace an exotic room-sized quantum computing "laser park" with miniaturized, commercial microwave technology similar to that used in smart phones.

Microwaves, the carrier of wireless communications, have been used in past experiments to manipulate single ions. But the NIST group is the first to position microwaves sources close enough to the ions—just 30 micrometers away—and create the conditions enabling entanglement, a quantum phenomenon expected to be crucial for transporting information and correcting errors in quantum computers.

Described in the August 11 issue of Nature, the experiments integrate wiring for microwave sources directly on a chip-sized ion trap and use a desktop-scale table of lasers, mirrors and lenses that is only about one-tenth of the size previously required. Low-power ultraviolet lasers are still needed to cool the ions and observe experimental results but might eventually be made as small as those in portable DVD players. Compared to complex, expensive laser sources, microwave components could be expanded and upgraded more easily to build practical systems of thousands of ions for quantum computing and simulations.

"It's conceivable a modest-sized quantum computer could eventually look like a smart phone combined with a laser pointer-like device, while sophisticated machines might have an overall footprint comparable to a regular desktop PC," says NIST physicist Dietrich Leibfried, a co-author of the new paper.

"Although quantum computers are not thought of as convenience devices that everybody wants to carry around, they could use microwave electronics similar to what is used in smart phones. These components are well developed for a mass market to support innovation and reduce costs. The prospect excites us."

Quantum computers would harness the unusual rules of quantum physics to solve certain problems—such as breaking today's most widely used data encryption codes—that are currently intractable even with supercomputers. A nearer-term goal is to design quantum simulations of important scientific problems, to explore quantum mysteries such as high-temperature superconductivity, the disappearance of electrical resistance in certain materials when sufficiently chilled.

Read more from the official release.