Diamond microstructures for quantum information technologies

Much research effort is currently invested in the field of quantum information, based on the idea that information can be stored, transmitted, and manipulated using the fundamental quantum nature of matter. Quantum cryptography systems in which quantum bits of information - or qubits as they are known - are encoded onto single photons of light, are now commercially available, providing 100% secure data communication. Quantum computing, the execution of calculations using quantum mechanics, has yet to be realized on a useful scale, but offers the prospect of being able to solve problems so complex that a conventional computer would never be expected to finish them.Quantum information devices require strong suppression of 'noisy' processes in order to work effectively, since quantum states in matter are very fragile and can easily be destroyed before they have performed their tasks. This is can be achieved in the laboratory by operating at very low temperatures, or by isolating individual atoms in optical trap, but such techniques are not very practical for everyday devices. Diamond is attractive as it is a material that is intrinsically 'quiet', even at room temperature. There are few thermal vibrations, as the rigid structure means that energy needed to excite each vibration is large, there are few free electrons (diamond is a good electrical insulator), and there are few spins on the carbon nuclei that can fluctuate and interfere with the qubits. These factors combine to make diamond an excellent material from which to fashion quantum information devices. However there is a drawback / diamond, being such a hard material, is difficult to process into the device structures that we need to be able to construct the basic elements for our quantum information technology. This proposal seeks funding for a visit to the UK by one of the world's leading experts in diamond materials processing, Professor Steven Prawer of the University of Melbourne, Australia. Professor Prawer has recently developed methods for producing micrometer scale structures of diamond that make possible the creation of novel quantum devices. In particular, his research group can make structures that contain deliberately implanted defects to host electron-based qubits, and that are capable of storing light so as to provide control over the interaction between electrons and photons, a critical factor in many designs for quantum information devices and one that has yet to be achieved in diamond. We propose to use the visit to perform some of the first experiments in this important field, and to plan advanced experiments to build and test devices for quantum computing and quantum communications. The visit will also provide opportunities for other members of the UK diamond and quantum information research community to meet Professor Prawer and learn more about his new capabilities.