Quantum Technologies Based on Single Spins in the Solid-State - Tales from Quantum Computing to Quantum Probes in Biology

Professor Lloyd Hollenberg

Centre of Excellence for Quantum Computation and Communication Technology, School of Physics, University of Melbourne

3:30 pm Friday, 14 September 2012, EN103 Lecture Theatre (EN Building), Hawthorn.

The ability to control and measure individual spins in the solid-state opens new and wonderful possibilities for a class of quantum technologies where the operation is predicated on the weirder properties of quantum mechanics: superposition and entanglement. In this talk I will focus on single spin qubits based on defects/donors in two well known materials - silicon and diamond. In the case of silicon, spins associated with donor atoms form controllable spin-1/2 qubits with extremely long lived quantum coherence at cryogenic temperatures, and provide the building blocks of a silicon quantum computer. I will review the progress in the field, which is accelerating rapidly, and our work on the prospects and challenges for scaling up few qubit devices to a full blown quantum computer. In the case of diamond, the spin associated with the nitrogen-vacancy (NV) centre forms a spin-1 system whose levels can be controlled as a two-level qubit and read-out optically. Remarkably, even at room temperature the quantum coherence of the NV centre is relatively long lived, and given the bio-friendly nature of the diamond host material the NV centre has great potential as a magnetic probe of nanoscale biological environments. In contrast to quantum computing applications where we must protect the qubits from the environment at all costs, here we seek to expose the NV qubit to the worst possible environment - room temperature biology. Progress towards this goal will be reviewed, including our work on measuring NV qubits in a living cell, and the detection of near individual spin-labelled lipids and free-radicals in an artificial cell membrane

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