Shuttling-based trapped-ion quantum information processing
V. Kaushal, Bjoern Lekitsch, Alexander Stahl, Janine Hilder, D. R. M. Pijn, Christian Tomás Schmiegelow, A. Bermúdez, Markus Müller, Ferdinand Schmidt‐Kaler, Ulrich Poschinger
Moving trapped-ion qubits in a microstructured array of radiofrequency traps offers a route toward realizing scalable quantum processing nodes. Establishing such nodes, providing sufficient functionality to represent a building block for emerging quantum technologies, e.g., a quantum computer or quantum repeater, remains a formidable technological challenge. In this review, the authors present a holistic view on such an architecture, including the relevant components, their characterization, and their impact on the overall system performance. The authors present a hardware architecture based on a uniform linear segmented multilayer trap, controlled by a custom-made fast multichannel arbitrary waveform generator. The latter allows for conducting a set of different ion shuttling operations at sufficient speed and quality. The authors describe the relevant parameters and performance specifications for microstructured ion traps, waveform generators, and additional circuitry, along with suitable measurement schemes to verify the system performance. Furthermore, a set of different basic shuttling operations for a dynamic qubit register reconfiguration is described and characterized in detail.
Moving trapped-ion qubits in a microstructured array of radiofrequency traps offers a route toward realizing scalable quantum processing nodes. Establishing such nodes, providing sufficient functionality to represent a building block for emerging quantum technologies, e.g., a quantum computer or quantum repeater, remains a formidable technological challenge. In this review, the authors present a holistic view on such an architecture, including the relevant components, their characterization, and their impact on the overall system performance. The authors present a hardware architecture based on a uniform linear segmented multilayer trap, controlled by a custom-made fast multichannel arbitrary waveform generator. The latter allows for conducting a set of different ion shuttling operations at sufficient speed and quality. The authors describe the relevant parameters and performance specifications for microstructured ion traps, waveform generators, and additional circuitry, along with suitable measurement schemes to verify the system performance. Furthermore, a set of different basic shuttling operations for a dynamic qubit register reconfiguration is described and characterized in detail.
Moving trapped-ion qubits in a microstructured array of radiofrequency traps offers a route towards realizing scalable quantum processing nodes. Establishing such nodes, providing sufficient functionality to represent a building block for emerging quantum technologies, e.g. a quantum computer or quantum repeater, remains a formidable technological challenge. In this review, we present a holistic view on such an architecture, including the relevant components, their characterization and their impact on the overall system performance. We present a hardware architecture based on a uniform linear segmented multilayer trap, controlled by a custom-made fast multi-channel arbitrary waveform generator. The latter allows for conducting a set of different ion shuttling operations at sufficient speed and quality. We describe the relevant parameters and performance specifications for microstructured ion traps, waveform generators and additional circuitry, along with suitable measurement schemes to verify the system performance. Furthermore, a set of different basic shuttling operations for dynamic qubit register reconfiguration is described and characterized in detail.
Scalable trapped-ion quantum computing requires fast and reliable transport of ions through complex, segmented radiofrequency trap architectures without inducing excessive motional excitation. We present a numerical toolchain for the systematic generation of time-dependent electrode voltages enabling fast, low-excitation ion shuttling in segmented radiofrequency traps. Based on a model of the trap electrode geometry, the framework combines an electrostatic field solver, efficient unconstrained optimization, waveform postprocessing, and dynamical simulations of ion motion to compute voltage waveforms that realize prescribed transport trajectories while respecting experimental constraints such as voltage limits and bandwidth. The toolchain supports arbitrary trap geometries, including junctions and multi-zone layouts, and allows for the flexible incorporation of optimization objectives. We provide a detailed assessment of the accuracy of the framework by investigating its numerical stability and by comparing measured and predicted secular frequencies. The framework is optimized for numerical performance, enabling rapid numerical prototyping of trap architectures of increasing complexity. As application examples, we apply the framework to the transport of a potential well along a linear, uniformly segmented trap, and we compute a solution for shuttling a potential well around the corner of an X-type trap junction. The presented approach provides an extensible and highly efficient numerical foundation for designing and validating transport protocols in current and next-generation trapped-ion processors.
Scalable trapped-ion quantum computing requires fast and reliable transport of ions through complex, segmented radiofrequency trap architectures without inducing excessive motional excitation. We present a numerical toolchain for the systematic generation of time-dependent electrode voltages enabling fast, low-excitation ion shuttling in segmented radiofrequency traps. Based on a model of the trap electrode geometry, the framework combines an electrostatic field solver, efficient unconstrained optimization, waveform postprocessing, and dynamical simulations of ion motion to compute voltage waveforms that realize prescribed transport trajectories while respecting experimental constraints, such as voltage limits and bandwidth. The toolchain supports arbitrary trap geometries, including junctions and multi-zone layouts, and allows for the flexible incorporation of optimization objectives. We provide a detailed assessment of the accuracy of the framework by investigating its numerical stability and by comparing measured and predicted secular frequencies. The framework is optimized for numerical performance, enabling rapid numerical prototyping of trap architectures of increasing complexity. As application examples, we apply the framework to the transport of a potential well along a linear, uniformly segmented trap, and we compute a solution for shuttling a potential well around the corner of an X-type trap junction. The presented approach provides an extensible and highly efficient numerical foundation for designing and validating transport protocols in current and next-generation trapped-ion processors.
Current trapped-ion quantum computer architectures based on segmented traps utilize shuttling operations to establish connectivity between multiple sub-registers within one quantum processing unit. Complex trap architectures, including racetrack loops and junctions, offer prospects for increased scalability and have been successfully built and demonstrated. As hardware capabilities evolve, the need arises for additional automated software layers within the control stack for managing qubit routing. We present the automated generation of shuttling schedules for a branched ID architecture within a shuttling compiler that requires the integration of junctions. This not only provides the means for leveraging future new hardware advances, but also allows guiding the development of future architecture via resource estimation. Testing a wide range of quantum circuits, the junction-enabled shuttling compiler is able to reduce the necessary operations by a factor > 50 for translations and > 20 for separation/merge as compared to a linear architecture.
Shuttle-based trapped ion quantum processors typically employ a one-dimensional (1D) linear architecture to transport ion-qubits between one ore more laser interaction zones where the quantum gates are implemented, along with several qubit register storage segments. The two-dimensional (2D) quantum CCD architecture employs also T- or X-junctions for an improved scaling and efficiency. Here, we explore the shuttling layer in the compilation of quantum algorithm typical building blocks in such architecture. To weight the effort of linear shuttle and junction shuttle, we introduce individual cost functions for each operation. This allows comparing the total cost for quantum circuit building blocks such as the QFT, Carry, Adder, Shift, and Comparator circuits. We study their scaling properties with increased qubit numbers. At equivalent transport cost for junction and linear shuttling, we show that 2D architectures outperform the 1D linear trap with the ratio improving as the number of ions increases. Finally, we discuss the use of cells, such that the entire processor is constructed from a 2D array of such interconnected cells. The work aims to optimize quantum processor architectures, implementing a co-design that fits to the specific task and scaling up in a shuttle-efficient way.
Ion trap technologies have earned significant attention as potential candidates for quantum information processing due to their long decoherence times and precise manipulation of individual qubits, distinguishing them from other candidates in the field of quantum technologies. However, scalability remains a challenge, as introducing additional qubits into a trap increases noise and heating effects, consequently decreasing operational fidelity. Trapped-ion Quantum Charge-Coupled Device (QCCD) architectures have addressed this limitation by interconnecting multiple traps and employing ion shuttling mechanisms to transfer ions among traps. This new architectural design requires the development of novel compilation techniques for quantum algorithms, which efficiently allocate and route qubits, and schedule operations. The aim of a compiler is to minimize ion movements and, therefore, reduce the execution time of the circuit to achieve a higher fidelity. In this paper, we propose a novel approach for initial qubit placement, demonstrating enhancements of up to 50% compared to prior methods. Furthermore, we conduct a scalability analysis on two distinct QCCD topologies: a 1D-linear array and a ring structure. Additionally, we evaluate the impact of the excess capacity - i.e. the number of free spaces within a trap - on the algorithm performance.