This paper proposes a scalable control device architecture for trapped-ion quantum computers based on microwave quantum control. While microwave control of trapped-ion qubits offers high gate fidelity, it requires high-precision and scalable microwave control devices. In the control devices for microwavebased trapped-ion quantum computers, three types of signals need to be managed: (1) wideband microwaves with low phase noise for quantum gate operations, (2) numerous signals with sub-microsecond voltage changes to implement the quantum charge-coupled device (QCCD) architecture, and (3) triggers to synchronize measurement instruments. The proposed architecture combines heterogeneous control devices tailored to these three types of signals to achieve the required precision and scalability at a practical cost. The system features a shared sequencer that can manage all units uniformly, ensuring scalability and reducing development costs. To correctly execute the control sequences, it is necessary to align the operating timing of each unit. In the proposed system, each unit maintains a common time and independently issues events by referring to this time. High-precision time synchronization protocols based on IEEE1588 can be used for time synchronization. In addition to that, multiple control devices can be expanded by combining fine-grained synchronization mechanisms using time synchronization and shared reference signals. This paper details the specifications required for trappedion quantum computers using microwaves and proposes an architecture that meets these specifications.
This paper proposes a scalable control device architecture for trapped-ion quantum computers based on microwave quantum control. While microwave control of trapped-ion qubits offers high gate fidelity, it requires high-precision and scalable microwave control devices. In the control devices for microwavebased trapped-ion quantum computers, three types of signals need to be managed: (1) wideband microwaves with low phase noise for quantum gate operations, (2) numerous signals with sub-microsecond voltage changes to implement the quantum charge-coupled device (QCCD) architecture, and (3) triggers to synchronize measurement instruments. The proposed architecture combines heterogeneous control devices tailored to these three types of signals to achieve the required precision and scalability at a practical cost. The system features a shared sequencer that can manage all units uniformly, ensuring scalability and reducing development costs. To correctly execute the control sequences, it is necessary to align the operating timing of each unit. In the proposed system, each unit maintains a common time and independently issues events by referring to this time. High-precision time synchronization protocols based on IEEE1588 can be used for time synchronization. In addition to that, multiple control devices can be expanded by combining fine-grained synchronization mechanisms using time synchronization and shared reference signals. This paper details the specifications required for trappedion quantum computers using microwaves and proposes an architecture that meets these specifications.
This paper proposes a control system capable of supporting various qubit platforms by combining control units with different specifications with a lightweight and common interface. To realize quantum computers, several qubit platforms, such as superconducting qubits, neutral atoms, ion traps, and semi-conductor quantum dots, are being researched. Each platform requires different microwave frequencies, channel numbers, intensities, and time scales for control. However, building individual control systems for each platform is not practical from a development cost perspective. Therefore, the standardization of control systems is desired. In practice, common languages and libraries for pulse control software are being developed as both commercial products and open-source projects. However, no widely adopted standardization methods currently exist for the control layer of electrical signals responsible for qubit manipulation. This paper first organizes the challenges in standardizing the control layer of electrical signals. It then proposes an architecture to address these challenges, featuring Ethernet-based unit inter-connections, a synchronization system based on time and pulses, and a lightweight and flexible waveform generation method. The proposed approach allows for practical cost adaptation to various types of qubits by connecting electronic circuits with specifications required for the target qubit platform.
Abstract The trapped-ion quantum charge-coupled device (QCCD) proposal1, 2 lays out a blueprint for a universal quantum computer that uses mobile ions as qubits. Analogous to a charge-coupled device (CCD) camera, which stores and processes imaging information as movable electrical charges in coupled pixels, a QCCD computer stores quantum information in the internal state of electrically charged ions that are transported between different processing zones using dynamic electric fields. The promise of the QCCD architecture is to maintain the low error rates demonstrated in small trapped-ion experiments3–5 by limiting the quantum interactions to multiple small ion crystals, then physically splitting and rearranging the constituent ions of these crystals into new crystals, where further interactions occur. This approach leverages transport timescales that are fast relative to the coherence times of the qubits, the insensitivity of the qubit states of the ion to the electric fields used for transport, and the low crosstalk afforded by spatially separated crystals. However, engineering a machine capable of executing these operations across multiple interaction zones with low error introduces many difficulties, which have slowed progress in scaling this architecture to larger qubit numbers. Here we use a cryogenic surface trap to integrate all necessary elements of the QCCD architecture—a scalable trap design, parallel interaction zones and fast ion transport—into a programmable trapped-ion quantum computer that has a system performance consistent with the low error rates achieved in the individual ion crystals. We apply this approach to realize a teleported CNOT gate using mid-circuit measurement6, negligible crosstalk error and a quantum volume7 of 26 = 64. These results demonstrate that the QCCD architecture provides a viable path towards high-performance quantum computers.
This thesis describes the development of technology and experimental techniques for scalable trapped-ion quantum computing. An architecture for scalable quantum computing is presented in which 171Yb+ ions are trapped in linear R.F. Paul traps and their hyper-fine states are used to form qubits. Quantum logical operations can be carried out by applying R.F. and microwave fields. This thesis presents significant improvements in the experimental setup used for quantum computing, as well as new theoretical developments and experimental demonstrations of new high- fidelity quantum control methods. A new procedure for carrying out high- delity two qubit gates using static magnetic eld gradients and resonant microwave elds is presented. It is shown that this has the potential to enable signi cantly improved delities compared to current methods. Improved methods for measurement and statistical analysis in trapped-ion experiments are also shown. These should enable more accurate measurement of two-qubit gate delities, which becomes increasingly important as delities increase. A new system for generating arbitrary R.F. and microwave waveforms is presented, including a bespoke software control system allowing the user to de ne custom pulse sequences, which represents a signi cant improvement in the scalability of the quantum control system. Experimental developments towards a system for carrying out on-chip trapped-ion quantum logic in a static magnetic eld gradient are also presented. A new technique for generating multi-level control methods is introduced, based on reducing a multi-level system to an e ective two-level system. High- delity quantum control methods generated using this technique, which form a will form a key part of the scalable quantum computing architecture, are implemented experimentally.
The availability of a universal quantum computer may have a fundamental impact on a vast number of research fields and on society as a whole. An increasingly large scientific and industrial community is working toward the realization of such a device. An arbitrarily large quantum computer may best be constructed using a modular approach. We present a blueprint for a trapped ion-based scalable quantum computer module, making it possible to create a scalable quantum computer architecture based on long-wavelength radiation quantum gates. The modules control all operations as stand-alone units, are constructed using silicon microfabrication techniques, and are within reach of current technology. To perform the required quantum computations, the modules make use of long-wavelength radiation-based quantum gate technology. To scale this microwave quantum computer architecture to a large size, we present a fully scalable design that makes use of ion transport between different modules, thereby allowing arbitrarily many modules to be connected to construct a large-scale device. A high error-threshold surface error correction code can be implemented in the proposed architecture to execute fault-tolerant operations. With appropriate adjustments, the proposed modules are also suitable for alternative trapped ion quantum computer architectures, such as schemes using photonic interconnects.
Trapped-ion quantum computers exhibit promising potential to provide platforms for high-quality qubits and reliable quantum computation. The quantum charge coupled device (QCCD) architecture is a leading example that offers a modular solution to enable the realization of scalable quantum computers, paving the way for practical quantum algorithms with large qubit numbers. Within these devices, ions can be shuttled (moved) throughout the trap and through different dedicated zones, e.g., a memory zone for storage and a processing zone for the actual computation. However, due to decoherence of the ions’ quantum states, the qubits lose their quantum information over time. Thus, the required time steps of shuttling operations should be minimized. In this work,1 we propose a heuristic approach to determining an efficient shuttling schedule, which orchestrates the movement operations within the device. Given a quantum algorithm and a device architecture, the proposed approach produces shuttling schedules with a close-to-minimal amount of time steps for small-size QCCD architectures. For large-scale QCCD devices, empirical evaluations show promising results with respect to quality of the solution as well as performance. An implementation of the proposed approach is publicly available as part of the open-source Munich Quantum Toolkit (MQT) athttps://github.com/cda-tum/mqt-ion-shuttler.
Quantum computing requires scalable control hard-ware capable of generating precise signals and synchronizing operations across large numbers of qubits. However, existing control systems are typically optimized for specific qubit modalities, leading to limited interoperability, high development cost, and poor scalability as device architectures evolve. To address this challenge, a heterogeneous and modular control architecture supporting multiple qubit platforms was previously proposed.This paper evaluates FPGA resource requirements and implementation characteristics of the architecture across four controller variants targeting high-frequency microwave, mid-frequency RF, low-frequency DAC, and digital GPIO applications. The results show that core architectural components—including networking, synchronization, and waveform generation—maintain nearly constant hardware usage across platforms, while resource scaling primarily depends on data throughput requirements rather than architectural complexity.Moreover, the architecture is demonstrated on both high-end FPGAs with high-bandwidth memory and cost-efficient embedded devices, confirming portability and deployment flexibility. These findings validate the feasibility of a unified control framework suitable for heterogeneous quantum systems and large-scale control networks.