Quantum control with trapped ions

Using trapped ions to develop efficient and robust quantum control

The primary focus of our research on trapped ions is the development of efficient and robust control techniques for arbitrary quantum systems in the presence of environmental noise.

Decoherence – the decay of the "quantumness" of a state – is a major challenge for any quantum system, and requires a dedicated effort to produce error-resistant approaches to quantum control.

Open-loop coherent control protocols provide a means to dynamically suppress random errors in quantum systems, addressing a primary challenge in quantum technology. Our work aims to expand the efficacy and applicability of dynamical decoupling for use in any coherent technology – establishing a fundamental role for these techniques as quantum firmware. We have recently formulated an efficient and user-friendly "filter-design" framework to understanding the performance of various open-loop control protocols. Outstanding challenges include the suppression of universal decoherence, the development of new optimization techniques, and the dynamical protection of nontrivial logic operations.

Our experimental efforts employ trapped atomic ions as a model quantum system, and permit detailed studies of quantum dynamics in noisy environments.

Quantum-Enabled Sensing

Trapped ions are exquisite sensors of external forces and fields. Experiments have demonstrated that trapped ion crystals are the most sensitive force detectors known, outperforming rival technologies by more than three orders of magnitude. Our work in this field has earned M. J. Biercuk the 2011 NMI Prize for Excellence in Measurement Science.

We are exploiting normal modes of ion motion, spin coherence, and novel quantum control techniques to produce novel force and field sensors with unrivalled performance. Ultimately we hope to produce deployable ion-based sensors leveraging the device fabrication capabilities of the Australian Institute of Nanoscience.

Quantum Simulation and Large-Scale Entanglement

Our work aims to study the dynamics of large-scale entangled systems and to produce useful, controllable quantum simulators. This work involves detailed theoretical studies and experiments using trapped atomic ions.

Ion crystals in a Penning trap provide a two-dimensional qubit array with regular structure. This system is ideal for the realization of large-scale entanglement via state-selective spin-motional interaction. Our work aims to produce entangled states of more than 100 particles with tunable interactions, for studies of the dynamics of entangled states. The particular states we are aiming to create may prove useful for simple tasks in quantum simulation and the evaluation of the robustness of real quantum simulators to environmental decoherence.