Eliza Cornell: Preserving Information in Quantum Systems via Coherent Driving

The first part of the talk will discuss our experimental demonstration of a method to extend the electron spin coherence time of the silicon vacancy center (SiV) in diamond. The SiV is an optically active defect with exceptionally high spin-strain susceptibility, making it a promising candidate for storing and processing quantum information encoded on phonons. The interaction between a spin and a phonon can be enhanced by a mechanical cavity, but the fidelity of the information exchange is limited by the spin coherence time. Under currently accessible parameter regimes, standard pulsed dynamical decoupling techniques to extend the coherence time are not compatible with a controllable spin-cavity interaction. We demonstrate an alternative noise decoupling scheme using a continuous coherent mechanical drive. We additionally demonstrate ultrafast spin Rabi rates of ~800MHz enabled by the SiV’s strong spin-strain interaction. The second part of the talk will introduce a scheme for inducing artificial cycling transitions in atomic systems without inherent cycling transitions, which has the potential to improve state readout fidelity and enable single-shot measurements. By coherently driving the excited state manifold, we can exploit the phenomenon of coherent interference of decay such that the undesired decay paths cancel out, effectively creating a cycling transition. I will discuss the sorts of atomic systems which are candidates for this scheme, and show computational results quantifying the expected increase in cyclicity. Eliza Cornell completed her PhD research in Marko Lončar’s lab at Harvard University. She received a B.S. in Engineering Physics from Stanford University in 2018, where she worked in Jelena Vučković’s group on silicon vacancy centers and integrated photonic devices. She also previously worked in Hugues de Riedmatten’s group at ICFO, doing research on rare earth ions in fiber-based cavities.