Breakthrough towards Diamond-Based Quantum Network

Element Six, the world leader in synthetic diamond supermaterials and member of the De Beers Group of Companies, today announced in collaboration with Delft University of Technology the entanglement of electron spin qubits (quantum bits) in two synthetic diamonds separated in space.

This breakthrough is a major step toward achieving a diamond-based quantum network, quantum repeaters and long-distance teleportation—changing the way information is processed and enabling new systems to efficiently tackle problems inaccessible by today's information networks and computers.

The collaboration, used two synthetic diamonds of millimeter-size that were grown by Element Six through chemical vapor deposition (CVD). The synthetic diamonds were engineered to contain a particular defect that can be manipulated using light and microwaves. The defect consists of a single nitrogen atom adjacent to a missing carbon atom—known as a nitrogen vacancy (NV) defect. The light emitted from the NV defect allows the defect's quantum properties to be 'read-out' using a microscope. By forming small lenses around the NV defect and carefully tuning the light emitted through electric fields, the Delft team was able to make the two NV defects emit indistinguishable particles of light (photons). These photons contained the quantum information of the NV defect and further manipulation allowed the quantum mechanically entanglement of the two defects.

"Element Six's synthetic diamond material has been at the heart of these important quantum mechanics developments, which promise to revolutionize information technologies," said Ronald Hanson , professor at Delft University of Technology. "Building on three years of collaboration, our research partnership has been critical in overcoming one of the greatest challenges of our time—finding and controlling a physical system suitable for fulfilling the promises of quantum entanglement. This is an important achievement that will help us not only create a quantum network to process information, but ultimately a future quantum computer."

The entanglement process, which Einstein called "spooky action at a distance," is a process where the two NV defects become strongly connected such that they are always correlated irrespective of the distance between them. The findings, published in this week's issue of "Nature," are a major leap forward for quantum science and demonstrate Element Six's ability to control a single atom-like defect in the diamond lattice at the parts per trillion level. It is the first time that qubits in two separated diamonds have been entangled and subsequently shown to behave as a single particle. This entangled state holds the potential for ensuring complete security in future information networks.

"The field of synthetic diamond science is moving very quickly, requiring us to develop CVD techniques that produce exceptionally pure synthetic diamond material at nano-engineering levels," said Adrian Wilson , head of Element Six Technologies. "Additionally, by applying the invaluable knowledge gained in our research, we're able to successfully develop and advance extreme performance solutions for our customers that capitalize on synthetic diamond's unique combination of properties, which can subsequently be leveraged across a range of industries."

Element Six collaborates with a number of universities to develop cutting-edge synthetic diamond solutions, for application across multiple industries, such as semiconductors and optics. This latest breakthrough could enable new applications in quantum information science and quantum-based sensors, and future encryption-based networks for communications. DARPA (QuASAR) and European Union FP7 (DIAMANT) helped fund Element Six and Delft's quantum network research.

If you're interested in learning more about synthetic diamond's diverse properties and applications, please visit www.e6.com.