Quantum Diamonds

Abstract:Controlling quantum degrees of freedom in solids is an outstanding challenge in physics. Owing to strong interaction with the solid environment usually dephasing in fast and hence control is imperfect. Spins have turned out to be ideal candidates for solid state quantum systems, especially when incorporated into an otherwise spin free lattice made up from carbon like e.g. in diamond. Diamond has outstanding material properties, including ultrahardness and higher thermal conductivity than any other solid material. In addition, diamond has recently become much more attractive for solid-state electronics, with the development of techniques to grow high-purity, single-crystal synthetic diamonds and insert suitable impurities into them (doping). Pure diamond is an electrical insulator, but doped with boron, it can become a semiconductor with outstanding properties. It could be used for detecting ultraviolet light, ultraviolet light-emitting diodes and optics, and high-power microwave electronics. But the application that has many researchers excited is quantum spintronics, which could lead to a practical quantum computer, ultra¬secure communication and has the potential for revolutionizing imaging schemes. This is based on the fact that spins in diamond are exceptionally well shielded from their environment, allowing e.g. multipartite entangled states to be observed over ms in a room temperature solid [1]. The very same fact renders electron spins in diamond to be exceptionally high resolution magnetic field sensors [2]. The talk will highlight recent achievements in solid-state quantum physics with diamond, which may also have important spin off to other areas like e.g. biophysics. [1] P. Neumann et al. “Multipartite entanglement among single spins in diamond” Science 320 (2008) 1326[2] G. Balasubramanian “Nanoscale imaging magnetometry with diamond spins under ambient conditions” Nature 455 (2008) 648