Precision Quantum Control Engineering Using Trapped 171Yb+ Ions

Abstract

Quantum computation is a promising technology owing to the unique physical nature of quantum systems. Quantum computers have the potential to be as much as exponentially more efficient than today’s most powerful classical computer at certain tasks. One of the major challenges the scientific community must overcome, arises due to the intrinsic tendency of quantum information to be highly susceptible to environmental noise. This thesis presents work in developing and characterizing methods for precision quantum control in the presence of decoherence inducing noise, using trapped 171Yb+ ions as a model experimental platform. A flexible , robust microwave system is used to access the 12.6 GHz hyperfine qubit manifold in the outer S-shell orbital. The low phase noise characteristics of a microwave oscillator allow free-evolution coherence times in excess of three seconds, and operational fidelities F > 99.99%, characterized by randomized benchmarking. Starting from this relatively clean baseline, control techniques may be implemented in order to simulate a variety of realistic, time-dependent noise models, via arbitrary IQ modulation of the microwave source. A formalism for calculating the spectral noise filter functions of piece-wise constant control sequences is developed. The efficacy of this formalism is demonstrated by experimentally characterizing a variety of control protocols in the presence of engineered noise.