Scientists Stretch Out Diamond for Better Qubits

Researchers at the University of Chicago and Cambridge University have developed a new technique for creating better qubits by stretching thin films of diamond. According to the announcement, “One of the most promising types of qubits is made from diamonds. Known as Group IV color centers, these qubits are known for their ability to maintain quantum entanglement for relatively long periods, but to do so they must be cooled down to just a smidge above absolute zero. The team wanted to tinker with the structure of the material to see what improvements they could make—a difficult task given how hard diamonds are. But the scientists found that they could ‘stretch’ out the diamond at a molecular level if they laid a thin film of diamond over hot glass. As the glass cools, it shrinks at a slower rate than the diamond, slightly stretching the diamond’s atomic structure—like pavement expands or contracts as the earth cools or warms beneath it.”

Stretching the diamond leads to some interesting effects. One significant benefit is that it could allow the quantum network to operate at a higher temperature. Of course, “higher” is a relative term. The new technique could lead to operating temperatures at 4 Kelvin, which is still very cold, but the path to absolute zero is asymptotic, and operating at 4 Kelvin could make “an order of magnitude difference in infrastructure and operating costs” when compared to current technology.

The stretched diamond material could also make it possible to control the qubits using microwaves instead of light in the optical spectrum, which would make it easier to exclude outside interference and significantly improve the fidelity of the system.

See the press release at the University of Chicago website for more information, or check out the full article at Physical Review X.