Q-bits from Nitrogen Vacancy Centers in Diamond

The first half of the talk is a background on nitrogen-vacancy defects. Some references on this are:

• Optical Properties of Solids by Mark Fox,
• Spin-flip and spin-conserving optical transitions of the nitrogen-vacancy centre in diamond, NJP 10, 045004 (2008)
• Ab initio supercell calculations on nitrogen-vacancy center in diamond: Electronic structure and hyperfine tensors, PRB 79, 075203 (2009)
• Quantum Mechanics by Landau and Lifshitz (good reference for symmetry groups)
  

The second half of the talk was based on the paper Coherent Dynamics of Coupled Electron and Nuclear Spins in Diamond. L. Childress et al., Science 314, 281 (2006)

Abstract: Understanding and controlling the complex environment of solid-state quantum bits is a central challenge in spintronics and quantum information science. Coherent manipulation of an individual electron spin associated with a nitrogen-vacancy center in diamond was used to gain insight into its local environment. We show that this environment is effectively separated into a set of individual proximal 13C nuclear spins, which are coupled coherently to the electron spin, and the remainder of the 13C nuclear spins, which cause the loss of coherence. The proximal nuclear spins can be addressed and coupled individually because of quantum back-action from the electron, which modifies their energy levels and magnetic moments, effectively distinguishing them from the rest of the nuclei. These results open the door to coherent manipulation of individual isolated nuclear spins in a solid-state environment even at room temperature.

**Groupmeeting by David McKay**