Physics & Astronomy Quantum Nano Seminar - Holger Haas, University of Waterloo
Title: "Controlling Nuclear Spins: Hyperpolarization and Decoupling in Non-standard Experimental Settings"
Abstract: This seminar has two somewhat independent parts: one on recent advances in incorporating Average Hamiltonian Theory (AHT) terms into numerical control finding algorithms and the other part about experiments on dynamical nuclear polarization (DNP) via optical pumping for phosphorus defects in silicon. We have developed tools for finding quantum control sequences designed to generate desired unitary operations while setting any number of arbitrary AHT terms to zero, that in the presence of deterministic pulse distortions as well as inhomogeneities in control amplitudes and level splittings. We have used such sequences in a force detected magnetic resonance imaging experiment and have demonstrated one dimensional imaging of proton spins with a resolution below 2 nm. I will also talk about recent optical pumping experiments on phosphorus defects in silicon using a previously unexplored technique to elucidate the nature of the DNP mechanism and investigate the characteristics of free exciton capture process.