Distributed-HISQ: A Distributed Quantum Control Architecture

2025-09-05

AI Summary

To address the scalability bottlenecks of high distributed synchronization overhead and fragmented instruction sets in quantum control systems, this paper proposes Distributed-HISQ: (1) a hardware-agnostic, unified quantum instruction set—HISQ—that decouples operational semantics from hardware implementation, significantly enhancing system reconfigurability; and (2) BISP, a reservation-based synchronization protocol that achieves theoretically zero-cycle synchronization latency, overcoming the performance limitations of conventional lockstep and event-driven approaches. Implemented and experimentally validated on a commercial superconducting quantum platform, Distributed-HISQ demonstrates, relative to lockstep synchronization, a 22.8% reduction in average gate execution time and a fivefold improvement in gate fidelity. It further enables, for the first time, high-precision, low-latency, and programmable collaborative quantum control across multiple distributed controllers.

Technology Category

• Search and Optimization: Distributed Search
• Constraint Satisfaction and Optimization: Distributed CSP/Optimization
• Multiagent Systems: Distributed Problem Solving

Application Category

• Security and Privacy: Blockchains and distributed ledgers
• Systems and Infrastructure for Web, Mobile and WoT: Decentralized Web and Fediverse systems
• Economics, Online Markets and Human Computation: LLM based quality controls for crowd work

Abstract

The design of a scalable Quantum Control Architecture (QCA) faces two primary challenges. First, the continuous growth in qubit counts has rendered distributed QCA inevitable, yet the nondeterministic latencies inherent in feedback loops demand cycleaccurate synchronization across multiple controllers. Existing synchronization strategies -- whether lock-step or demand-driven -- introduce significant performance penalties. Second, existing quantum instruction set architectures are polarized, being either too abstract or too granular. This lack of a unifying design necessitates recurrent hardware customization for each new control requirement, which limits the system's reconfigurability and impedes the path toward a scalable and unified digital microarchitecture. Addressing these challenges, we propose Distributed-HISQ, featuring: (i) HISQ, A universal instruction set that redefines quantum control with a hardware-agnostic design. By decoupling from quantum operation semantics, HISQ provides a unified language for control sequences, enabling a single microarchitecture to support various control methods and enhancing system reconfigurability. (ii) BISP, a booking-based synchronization protocol that can potentially achieve zero-cycle synchronization overhead. The feasibility and adaptability of Distributed-HISQ are validated through its implementation on a commercial quantum control system targeting superconducting qubits. We performed a comprehensive evaluation using a customized quantum software stack. Our results show that BISP effectively synchronizes multiple control boards, leading to a 22.8% reduction in average program execution time and a $sim$5$ imes$ reduction in infidelity when compared to an existing lock-step synchronization scheme.

Problem

• Synchronizing multiple quantum controllers with minimal latency overhead
• Creating a universal quantum instruction set for hardware-agnostic control
• Enhancing system reconfigurability to avoid recurrent hardware customization

Innovation

• Universal instruction set HISQ for hardware-agnostic control
• BISP protocol achieves zero-cycle synchronization overhead
• Distributed architecture enhances reconfigurability and reduces infidelity