http://www.researchonline.mq.edu.au/vital/access/services/Feed ${session.getAttribute("locale")} 5 http://www.researchonline.mq.edu.au/vital/access/manager/Repository/mq:15512 We map out the first excited state sublevel structure of single nitrogen-vacancy (NV) colour centres in diamond. The excited state is an orbital doublet where one branch supports an efficient cycling transition, while the other can simultaneously support fully allowed optical Raman spin-flip transitions. This is crucial for the success of many recently proposed quantum information applications of the NV defects. We further find that an external electric field can be used to completely control the optical properties of a single centre. Finally, a group theoretical mod el is developed that explains the observations and provides good physical understanding of the excited state structure. 2013-02-27T06:30:30.446Z ]]> http://www.researchonline.mq.edu.au/vital/access/manager/Repository/mq:9555 We describe how to design a large class of always on spin-1 interactions between polar molecules trapped in an optical lattice. The spin degrees of freedom correspond to the hyperfine levels of a ro-vibrational ground state molecule. Interactions are induced using a microwave field to mix ground states in one hyperfine manifold with the spin entangled dipole–dipole coupled excited states. Using multiple fields, anistropic models in one, two, or three dimensions can be built with tunable spatial range. An illustrative example in one-dimension is the generalized Haldane model, which at a specific parameter has a gapped valence bond solid ground state. The interaction strengths are large compared to decoherence rates and should allow for probing the rich phase structure of strongly correlated systems, including dimerized and gapped phases. 2010-09-24T07:40:36.951Z ]]> http://www.researchonline.mq.edu.au/vital/access/manager/Repository/mq:7412 We present a linear optics quantum computation scheme that employs an incremental parity encoding approach. The scheme uses techniques from cluster state computation and achieves comparable resource usage with increased tolerance to photon loss. 2010-03-17T01:20:24.249Z ]]>