What is it about?
Today's quantum computers execute programs using a small, fixed set of basic operations — like a calculator that only knows addition. Our work, ReQISC, upgrades quantum hardware to natively support any two-qubit operation, not just the standard few. We achieve this through two innovations: (1) a unified hardware control scheme that can execute any two-qubit gate at the fastest physically possible speed, working across different chip technologies; and (2) a purpose-built compiler that knows how to exploit this richer operation set to assemble quantum programs using far fewer steps. Tested on 132 real quantum programs, ReQISC cuts program execution time by 40–90% and reduces errors by up to 3.3x compared to conventional approaches, while keeping the engineering overhead manageable.
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Why is it important?
Quantum computers are notoriously error-prone: every operation introduces noise, so fewer operations mean more reliable results. For years, researchers have known that richer sets of quantum operations could theoretically reduce the number of steps needed to run a program, but nobody could make this work in practice — the calibration costs were too high and existing compilers couldn't take advantage. ReQISC is the first system to close this gap end-to-end: from hardware pulse control to program compilation, it makes the most expressive possible instruction set (the full SU(4) group) both performant and practical. This is timely because quantum hardware is at an inflection point — devices are large enough to attempt useful computations but still too noisy to run them reliably. By drastically reducing circuit depth and execution time without requiring new chip fabrication, ReQISC offers an immediately deployable path to higher-fidelity quantum computation on existing and near-future hardware.
Perspectives
This project grew from a simple frustration: the gap between what quantum hardware can physically do and what compilers ask it to do. Most quantum chips are capable of far more than CNOT gates, yet our entire software stack is built around that one primitive. Bridging this gap required us to think across traditional boundaries — from pulse-level physics to compiler design to systems architecture — and it was deeply rewarding to see how ideas from classical computer architecture (like instruction decoding and microarchitectural control logic) translated beautifully into the quantum domain. I'm especially proud that we evaluated ReQISC on 132 real programs rather than toy examples: it was important to us that this work be practical, not just theoretically elegant. I hope this paper encourages the community to rethink the quantum instruction set as a first-class design target — much as the RISC revolution reshaped classical computing decades ago.
Zhaohui Yang
Hong Kong University of Science and Technology
Read the Original
This page is a summary of: Reconfigurable Quantum Instruction Set Computers for High Performance Attainable on Hardware, March 2026, ACM (Association for Computing Machinery),
DOI: 10.1145/3779212.3790208.
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