News Article
Quantum hope with fake diamond
Element Six Advances make possible quantum grade purity synthetic diamond
Element Six, along with researchers at the universities of Paris and Stuttgart, has announced significant progress in the development of synthetic diamond suitable for the realisation of quantum computers capable of operating at room temperature. As the potential to apply the theory of quantum mechanics in practical applications such as computing and cryptography moves closer, the need for a high purity material that meets the requirements of these new markets becomes paramount.
The state of current research has been published as a letter in the latest edition of Nature Materials. In the paper, Ultralong spin coherence time in isotopically engineered diamond, researchers state the requirements for diamond with quantum grade purity. For Element Six this has meant developing synthesis processes based on chemical vapour deposition (CVD) that can produce ultrapure isotopically controlled single crystal diamond that has a remarkably low concentration of paramagnetic impurities.
“For quantum applications, Element Six has been faced with the challenge of simultaneously reducing the concentration of the isotope 13C to less than 0.3% and reducing the concentration of other paramagnetic defects to less than 1014 cm-3,” says Daniel Twitchen, senior researcher at Element Six and one of the paper’s authors. “This isotopically engineered diamond is essentially the first quantum grade purity diamond ever produced and marks a milestone for synthetic diamond produced by a CVD process.”
These recent results highlight the progress of research carried out under the three-year project called “Engineered Quantum Information in Nanostructured Diamond” or “EQUIND” which started in early 2007. EQUIND is part of the European Union’s “FET Open Funding Programme”, aimed at studying the potential of future and emerging technologies that may have an impact on society or industry. The project’s main aim is to establish whether specific optical features identified in diamond can be used as the basic elements for quantum computers and single-photon sources.
One of the requirements of practical quantum devices is that the individual quantum bits, or qubits – analogous to zeroes and ones of classical computers – need to store information for sufficient time to make many computational operations (>105). Any unintentional defects with paramagnetic spin in the diamond can result in the qubits rapidly losing their quantum information, severely limiting the number of possible computations. So researchers are putting a great deal of effort into increasing "coherence time" which is one of the many challenges to building practical computers. This requires developing quantum purity diamond with a very low defect spin concentration. In this letter to Nature Materials, the EQUIND consortium report, single electron spins having a room temperature spin dephasing time of 1.8 ms, the longest ever observed in a solid state system at room temperature.
Potential in other applications
Diamond with these properties is also applicable to research into a new type of nanometre-scale magnetic sensors that could be used in biological imaging. In their letter, the researchers note, “The ability of ultrapure isotopically controlled CVD diamond to detect weak magnetic fields with high local resolution might have implications in a wide range of fields such as: life science, metrology and quantum applications. A possible example are diamond magnetometers used to detect magnetic fields associated with the ion flow through membrane channels in cells.”
EQUIND is co-ordinated by the Ecole Normale Superieure de Cachan, near Paris and includes a total of eight groups of leading researchers from academia and industry. The other partners are the Universities of Bristol and Warwick in the UK, Stuttgart and Kiel Universities in Germany, the Academy of Science in Belarus, and the University of Melbourne in Australia. The consortium combines expertise in two different fields – diamond material synthesis and processing, and quantum information processing.
The state of current research has been published as a letter in the latest edition of Nature Materials. In the paper, Ultralong spin coherence time in isotopically engineered diamond, researchers state the requirements for diamond with quantum grade purity. For Element Six this has meant developing synthesis processes based on chemical vapour deposition (CVD) that can produce ultrapure isotopically controlled single crystal diamond that has a remarkably low concentration of paramagnetic impurities.
“For quantum applications, Element Six has been faced with the challenge of simultaneously reducing the concentration of the isotope 13C to less than 0.3% and reducing the concentration of other paramagnetic defects to less than 1014 cm-3,” says Daniel Twitchen, senior researcher at Element Six and one of the paper’s authors. “This isotopically engineered diamond is essentially the first quantum grade purity diamond ever produced and marks a milestone for synthetic diamond produced by a CVD process.”
These recent results highlight the progress of research carried out under the three-year project called “Engineered Quantum Information in Nanostructured Diamond” or “EQUIND” which started in early 2007. EQUIND is part of the European Union’s “FET Open Funding Programme”, aimed at studying the potential of future and emerging technologies that may have an impact on society or industry. The project’s main aim is to establish whether specific optical features identified in diamond can be used as the basic elements for quantum computers and single-photon sources.
One of the requirements of practical quantum devices is that the individual quantum bits, or qubits – analogous to zeroes and ones of classical computers – need to store information for sufficient time to make many computational operations (>105). Any unintentional defects with paramagnetic spin in the diamond can result in the qubits rapidly losing their quantum information, severely limiting the number of possible computations. So researchers are putting a great deal of effort into increasing "coherence time" which is one of the many challenges to building practical computers. This requires developing quantum purity diamond with a very low defect spin concentration. In this letter to Nature Materials, the EQUIND consortium report, single electron spins having a room temperature spin dephasing time of 1.8 ms, the longest ever observed in a solid state system at room temperature.
Potential in other applications
Diamond with these properties is also applicable to research into a new type of nanometre-scale magnetic sensors that could be used in biological imaging. In their letter, the researchers note, “The ability of ultrapure isotopically controlled CVD diamond to detect weak magnetic fields with high local resolution might have implications in a wide range of fields such as: life science, metrology and quantum applications. A possible example are diamond magnetometers used to detect magnetic fields associated with the ion flow through membrane channels in cells.”
EQUIND is co-ordinated by the Ecole Normale Superieure de Cachan, near Paris and includes a total of eight groups of leading researchers from academia and industry. The other partners are the Universities of Bristol and Warwick in the UK, Stuttgart and Kiel Universities in Germany, the Academy of Science in Belarus, and the University of Melbourne in Australia. The consortium combines expertise in two different fields – diamond material synthesis and processing, and quantum information processing.
