QuCtrl-BELL: A Compiler-Driven Sub-Microsecond Feedback Control Stack for Scalable Trapped-Ion Quantum Experiments

2026-05-21

AI Summary

This work addresses a fundamental conflict in scaling trapped-ion quantum computing: the stringent requirement for sub-microsecond board-level feedback imposes tight hardware-software coupling that compromises software maintainability and scalability. To resolve this, the authors propose QuCtrl-BELL—the first software stack to integrate compiler technology into trapped-ion control. By decoupling control flow (loops, branches, synchronization) from hardware state data, QuCtrl-BELL preserves high-level abstractions while generating deterministic, distributed board-level code. Its Python-embedded domain-specific language undergoes a six-stage compilation pipeline—including SSA transformation, liveness analysis, and graph-coloring register allocation—to produce compact step tables. Implemented on a RISC-V+PXIe platform, the system achieves feedback latency below 700 nanoseconds, demonstrating feasibility in programmability, timing determinism, and modularity.

Abstract

As trapped-ion quantum computing scales to larger qubit registers and more complex control protocols, classical control systems face a fundamental tradeoff: sub-microsecond board-level feedback requires tight hardware coupling, whereas maintainability and extensibility require clean, modular software abstractions. This paper presents QuCtrl-BELL (Bell), a compiler-driven software stack for trapped-ion quantum control. The design resolves this tradeoff by decoupling control flow -- including loops, branches, and synchronization -- from hardware state data. A Python-embedded domain-specific language (DSL) is lowered through a six-stage transpilation pipeline covering control flow graph (CFG) construction, static single-assignment (SSA) conversion, liveness analysis, and graph-coloring register allocation. The compiler generates deterministic distributed board-level programs and compact step-table data. A cross-board synchronization protocol supports feedback loops with latency below 700~ns without host intervention. Bell is deployed and evaluated on the QuCtrl-BELL platform (RISC-V + PXIe), demonstrating that a compiler-based infrastructure can provide programmability, deterministic timing, and modularity for scalable trapped-ion quantum control.

Problem

• trapped-ion quantum computing
• sub-microsecond feedback
• classical control systems
• hardware-software tradeoff
• scalable quantum control

Innovation

• compiler-driven control
• sub-microsecond feedback
• trapped-ion quantum computing
• domain-specific language (DSL)
• cross-board synchronization