Chip protects single atoms

Researchers from the Max Planck Institute for Quantum Physics and Ludwig Maximilians University in Germany have found a way to closely control the quantum states, or traits, of single atoms trapped in a microchip.

The method is a step toward building devices that depend on traits of single atoms, like miniature atomic clocks that are an order of magnitude more accurate than those that exist today, and quantum computers.

Quantum computers would use traits like orientation to store the ones and zeros of computer information, and would take advantage of the quirks of the laws of physics at the quantum scale to carry out fantastic numbers of computations in a relatively small number of steps.

The challenge to using single atoms to store information is that quantum states tend to be fragile, especially when they are in close contact with other materials..

The researchers' chip uses magnetic fields to hold neutral atoms 5 to 130 microns above the chip surface at room temperature. The chip preserve the atoms' quantum states for more than a second, plenty long enough for most quantum information processing needs.

The key was choosing the right quantum traits. The researchers use the atom's hyperfine levels, which are subtle sub levels of an atom's lowest energy, or ground, state.

The microchip trap is a step toward quantum computer chips that would integrate thousands of atoms.

A miniature atomic clock could become practical within three years, according to the researchers. Quantum processors are at least ten years away. The work appeared in the April, 2004 issue of Physical Review Letters.