Jewelry company, university make largest quantum memory Metal Tech News – May 4, 2022
A company that specializes in jewelry has teamed up with researchers to create a mind-blowing storage breakthrough – the collaboration resulting in the manufacture of a two-inch diamond wafer intended for quantum applications and is the largest diamond storage ever created, capable of holding up to 25 exabytes of information at room temperature.
"A 2-inch diamond wafer theoretically enables enough quantum memory to record 1 billion Blu-ray discs," said Adamant Namiki President and CEO Riyako Namiki. "This is equivalent to all the mobile data distributed in the world in one day."
For reference, 25 exabytes is 25 billion gigabytes (that is 25 with 18 zeros).
A joint effort between Adamant Namiki Precision Jewel Co. Ltd. and Saga University, the company said it originally produced a diamond wafer of this size in September last year, but that iteration of the process introduced too many impurities for the resulting diamond to be useful in quantum computers, so it spent the last few months investigating that problem.
Adamant Namiki says the new method that emerged from this work is able to "grow stress-free, high-quality, large-diameter diamond substrate for stable production" and is said to leave just three parts per billion of nitrogen in the resulting diamond.
This level of ultra-high purity is perfectly suited for quantum computers, quantum memory and quantum sensing devices.
In taking a step back to review the impurities, the initial challenge was to create a diamond wafer that was both pure and bigger than the current standard of four millimeters, which is too small to be practical.
This was no easy task, as making the diamonds for quantum computing involves using nitrogen, and to be useful as storage for quantum bits or qubits, a diamond must be very pure, with no contaminant rising above three parts per billion.
Previous attempts to make larger diamonds always introduced too much nitrogen. To achieve its goal, the team devised a new method to grow diamonds called step-flow.
According to the research team, this approach has the diamonds grow on top of a stair-shaped sapphire substrate. As the diamonds expand, they grow laterally, reducing cracking and anomalies. Nitrogen gas is used to accelerate the growth process, and this method devised by Adamant Namiki and Saga University reduces the amount of nitrogen required, which is the key to its success.
The resulting diamond has been named a Kenzan diamond.
Diamonds are seen as the ideal medium for quantum computing storage. This is due to a defect in their design called the nitrogen-vacancy center.
This defect occurs when one carbon atom in the diamond's crystal lattice is replaced by a nitrogen atom, with the adjacent lattice site left empty. This defect traps electrons, which is how it is used as storage.
Like most other computing systems, it is a binary system where the ensuing ones and zeroes are determined if an electron is detected or not – a detected electron being a one, whereas an absent electron is a zero. This allows diamonds to be written, erased, and rewritten endlessly and, theoretically, if never exposed to light, could hold data for eternity.
This marks a major breakthrough for quantum computing. The company says the wafers can be mass-produced and is expected to introduce them commercially by 2023.