Scalable, high-fidelity all-electronic control of trapped-ion qubits (2407.07694v1)

Abstract: The central challenge of quantum computing is implementing high-fidelity quantum gates at scale. However, many existing approaches to qubit control suffer from a scale-performance trade-off, impeding progress towards the creation of useful devices. Here, we present a vision for an electronically controlled trapped-ion quantum computer that alleviates this bottleneck. Our architecture utilizes shared current-carrying traces and local tuning electrodes in a microfabricated chip to perform quantum gates with low noise and crosstalk regardless of device size. To verify our approach, we experimentally demonstrate low-noise site-selective single- and two-qubit gates in a seven-zone ion trap that can control up to 10 qubits. We implement electronic single-qubit gates with 99.99916(7)% fidelity, and demonstrate consistent performance with low crosstalk across the device. We also electronically generate two-qubit maximally entangled states with 99.97(1)% fidelity and long-term stable performance over continuous system operation. These state-of-the-art results validate the path to directly scaling these techniques to large-scale quantum computers based on electronically controlled trapped-ion qubits.

• The paper presents an all-electronic control approach for trapped-ion qubits, achieving unprecedented fidelities of 99.999% for single-qubit and 99.97% for two-qubit operations.
• The methodology employs shared current-carrying traces and local tuning electrodes in a microfabricated chip, minimizing noise and crosstalk for scalable quantum operations.
• Experimental results using a seven-zone ion trap validate the design’s robustness and promise for cost-effective, large-scale quantum computing integration.

Scalable High-Fidelity All-Electronic Control of Trapped-Ion Qubits

The paper "Scalable, high-fidelity all-electronic control of trapped-ion qubits" investigates an innovative architecture for trapped-ion quantum computing that addresses the current scale-performance trade-offs faced by quantum computing devices. Traditionally, optical systems have been instrumental in quantum gate operations for trapped-ion qubits, but these systems face challenges in scalability due to the complexity and power demands. This paper introduces an alternative approach, utilizing all-electronic control, which simplifies the integration process while maintaining high levels of fidelity in quantum operations.

Architectural Design

The proposed architecture leverages shared current-carrying traces and local tuning electrodes within a microfabricated chip design. This configuration aims to perform quantum gates while minimizing noise and crosstalk, independent of the scale of the device. The design significantly departs from conventional systems by integrating control electronics with chip-scale fabrication, thus paving the way for large-scale manufacturing.

The system employs a shared AC magnetic drive implemented through current flows in integrated traces. This drive is crucial for executing both single- and two-qubit operations via the Mølmer–Sørensen interaction mechanism. The local tuning electrodes further allow for precise adjustments of these interactions on a zone-by-zone basis, facilitating robust, site-selective control among potentially thousands of qubits.

Experimental Demonstration

The researchers validated their approach using a prototype seven-zone ion trap capable of controlling up to ten qubits. They demonstrated single-qubit operations with an unprecedented fidelity of $99.99916(7)\%$. Moreover, they achieved two-qubit entangled states with a high fidelity of $99.97(1)\%$, demonstrating long-term stable operations over extended periods without significant decay in performance.

A significant part of the experimentation underscored the architecture's ability to suppress errors commonly encountered in quantum computing, such as magnetic interference and crosstalk. These results have profound implications for designing quantum computers with simplified, power-efficient hardware that doesn't compromise operational fidelity, even when scaled to larger systems.

Theoretical and Practical Implications

From a theoretical standpoint, this paper provides a viable route toward achieving high-coherence qubit operations without reliance on complex optical infrastructures. The all-electronic method proposed here offers a glimpse into a future where quantum computing systems are not only more powerful but also more compact and easier to manufacture using contemporary semiconductor technologies.

Practically, this architecture could revolutionize the semiconductor industry's role in quantum computing by emphasizing compatibility with foundry-based manufacturing, thus significantly reducing the engineering and cost barriers associated with current quantum device production. Moving forward, this approach aligns well with the modular scaling frameworks required for developing mid-scale quantum computers that could consist of thousands of qubits.

Future Directions

The findings and methods outlined in this paper suggest several directions for future research and development. Scaling up chip fabrication techniques, enhancing electromagnetic field stability, and integrating additional quantum logic functionalities directly into microfabricated chips could unlock further efficiencies and performance gains. Moreover, adapting these techniques to other qubit modalities might widen applicability and open new paths in the quest for practical quantum information processing devices. Collaboration with the semiconductor industry would be pivotal, promoting the standardization and mass deployment of quantum devices.

Ultimately, the research provides a solid foundation for the development of scalable, high-performance quantum computing systems, achieving a significant stride towards feasible commercial and scientific applications of quantum technology.