Introducing: larger quantum effects at room temperature

[Seze Mune]

Two research groups from the US, the UK and Germany have collaborated on producing a synthetic diamond which can retain information for nearly 2 seconds at room temperature. We're inching closer to a quantum computer!

"The scientists located an area in the diamond where a carbon 13 and a nitrogen ion are only about two nanometers apart. At that distance the spin of the nitrogen ion's electron and that of the nearby carbon nucleus couple together—the electron acts as a tiny magnetometer that reflects the carbon 13's nuclear spin state. By hitting the nitrogen vacancy center with laser light, the researchers can measure the electron's spin and, by extension, the spin of the carbon 13 nucleus.

"The catch is that the electron's spin is not as stable as the nuclear spin of the carbon atom; it fluctuates on the millisecond timescale. And once the electron changes its spin, the information in the qubit is lost. "A single electronic spin flip completely destroys the coherence of our nucleus," said Georg Kucsko, a member of Lukin's research group who presented at the meeting. To keep the electron's flip-flopping from affecting the nucleus, the researchers continually reset the electron's spin with green laser light, essentially turning off the interaction between electron and nucleus when that interaction is not needed.

"In order to make things better, you make it worse," says solid-state quantum physicist Fedor Jelezko of the University of Ulm in Germany, who was not part of the new research. "If the electron flips very fast, the nucleus will not see it anymore. It creates some average field that does not fluctuate."

"Using that tactic, along with a sequence of radio-frequency pulses to suppress interactions with other carbon nuclei in the diamond, the researchers were able to store quantum information at ambient temperatures for nearly two seconds. That is a significant leap from previous experiments, where storage times in single qubits have generally been measured in microseconds. "

[Tsyal Maktoyu]

Interesting, but still not viable for quantum computing IMO. Imagine trying to run billions of qubits at once, and the power draw it would take to keep flipping the spin of the electrons. And if even one flip is missed, it could cascade into other electrons (exclusion principle, after all)...and goodbye data.

Do you know by chance what ion of nitrogen it was?

Still quite a leap, though.

[Seze Mune]

Srane! One big step for qubit kind....   

[Tsyal Maktoyu]

Also, how exactly did they measure this? Quantum tunneling microscope?

[Seze Mune]

It really doesn't say.  But perhaps researching it from here might help:

"In the latest advance on that front, the research groups of Mikhail Lukin of Harvard University and Ignacio Cirac of the Max Planck Institute of Quantum Optics in Garching, Germany, and their colleagues encoded long-lived quantum information in the spin of a single-atom impurity in a synthetically produced diamond. Spin is a quantum property akin to the pointing of a particle's internal bar magnet, either up or down, representing 1 or 0."