QDev Seminar: Ed Barnes – University of Copenhagen

QDev Seminar: Ed Barnes

Toward a general approach to achieving robust quantum control

One of the greatest challenges in achieving control of microscopic quantum systems is the decoherence induced by the environment, a problem which pervades experimental quantum physics and is particularly severe in the context of solid state quantum computing and nanoscale quantum devices. I will present a general approach to constructing smooth, experimentally feasible driving fields which automatically cancel unknown noise-induced errors in a qubit's evolution. The analytical framework I will describe arises from combining recent methods for obtaining exact solutions to the time-dependent Schroedinger equation with ideas from topology. Our approach subsumes many well-known techniques for dynamical decoupling and dynamically corrected gates and enables access to the full solution space of error-correcting control sequences, thus providing far greater flexibility in overcoming decoherence.