B.B.C. Article
In a quantum computer, pure silicon is not enough - only one specific type of silicon atom will do.
The good stuff is silicon-28, and physicists in the US have worked out how to produce it with 40 times greater purity than ever before.
Even better, they can do it in the lab instead of relying on samples made ten years ago in a huge, repurposed plutonium plant in St Petersburg.



This promises to solve a serious supply problem in quantum computing research.
Several of the most promising schemes for building a quantum computer are based in silicon. One that has received much attention stores "qubits" in atoms of another element, like phosphorous, embedded in a tiny layer of ultra-pure silicon-28.
Qubits are the quantum replacement for bits - the ones and zeros that represent information inside a conventional computer. They promise to usher in a new era of computing because they can simultaneously encode a one and a zero, enabling incredibly fast and complex calculations.

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Sgt Kelly wrote:Does that mean we have to go back to the moon and replace the gold disk ?

The laser reflector consists of 100 fused silica half-cubes, called corner cubes, mounted in a 46-centimeter square aluminum panel. Each corner cube is 3.8 centimeters in diameter. Corner cubes reflect a beam of light directly back toward the point of origin.

Sgt Kelly wrote:I'm talking out of my ass.

Firstly I was thinking of the golden records that were sent along with the Voyager spacecraft.

Secondly I was led to believe that some universal constants were mentioned on this record to indicate to any extraterrestrials that we are aware of them. This is apparently not the case.

campermon wrote:One of my favourite images from the golden discs:

scott1328 wrote:I've heard there is an effort underway using this pure silicon to precisely determine Avogadro's constant and from this redefine the kilogram as being the mass of a specific number of silicon atoms.

newolder wrote:Marcus du Sautoy covered this in his Precision series on the beeb... Episode 2 at this link http://www.bbc.co.uk/programmes/b02xbjmf/episodes/guide but the content is behind a paywall.

Silicon isotopes distorted the first attempt, iirc.

scott1328 wrote:Is there an element with only 1 stable isotope?

campermon wrote:

scott1328 wrote:Is there an element with only 1 stable isotope?

http://en.wikipedia.org/wiki/Monoisotopic_element