Quantum Control Engineering with Trapped Ions

J. F. Poyatos, S. A. Gardiner, R. Walser +3 more

Selwyn Simsek, Florian Mintert

Invariant-based inverse engineering is an elegant approach to quantum control with corresponding experimental implementations that perform tasks with applications in quantum information processing such as shuttling trapped ions. We build on recent work to generalise invariant-based inverse engineering to control two coupled harmonic oscillators in any number of spatial dimensions. This may be used to perform experimentally relevant tasks such as separation of trapped ions, which is demonstrated numerically, achieving transfer fidelities of over 96% as well as low motional number excitations.

Q. A. Turchette, B. E. King, Christopher J. Myatt +6 more

Abdessamad Belfakir, Yousra Bouasria, HERSCHEL A. RABITZ +1 more

We demonstrate coherent control of motional dynamics in trapped Rydberg ions engineered to exhibit a conical intersection between adiabatic potential-energy surfaces. Using quantum optimal control, an optimally shaped electric field drives the motional wave packet between prescribed spatial configurations on microsecond timescales. Localized nonadiabatic coupling breaks the symmetry of the dynamics and produces a directed trajectory: after only a few early passages through the conical intersection region, the packet proceeds toward the target with high fidelity. In contrast, in the Born-Oppenheimer limit, where such coupling is absent, the optimized control yields symmetric, multicycle oscillations rather than a comparably directed displacement. While both approaches reach the target at the chosen final time, the underlying trajectories are qualitatively different. This work demonstrates that engineered conical intersections can serve as a potential control resource for directional motional dynamics, complementing pulse-shaping methods in trapped-ion systems. This directional motion of the ions, enabled by the conical intersection, may provide a route toward improved control of motional states in trapped-ion quantum information processing.

Brian King

Stefanie Castillo

[Background] Ions in an ion trap are among the most promising technologies to implement a quantum processor. This machine is governed by a classic electronic control system, for which we found no systematic electronic system-level approach for its conception, design, implementation, and/or verification. The trapped-ion quantum processor cannot advance its roadmap without an appropriate and fitting electronic control system. To fully enable further advancements in the field, an understanding of the electronic control system as a system of its own and the conception of its electronic system-level description, are due needed. [Objective] Therefore, we want to address the electronic control system of a trapped-ion quantum processor as a system of its own by first identifying its published literature. [Method] For that purpose, we conducted a systematic literature review abiding by the APISSER methodology for systematic literature reviews in engineering, which describes and delimits the reach of this study. [Results] In this paper, we report the results of the study, classify them, and present possible research directions and considerations to be taken in the conception of this system. [Conclusion] This study lays a introductory foundation to grasp the requirements and environment of the electronic control system of a trapped-ion quantum processor. A foundation much needed to leverage further research on this topic by the engineering community. Furthermore, it serves as a checkpoint in time: listing and synthesizing, the existing published body-of-knowledge of this topic within the defined boundaries of our method.