QROB reveals hidden costs in quantum program compilation efficiency
QROB: Quantifying Realization Overhead in Quantum Compilation via Reverse Construction
Hardware Architecture
Summary
Quantum computers need to rearrange instructions so they fit the real connections between their parts, but this often adds extra steps. The researchers developed QROB, a new way to track and measure these extra steps by working backward from configurations that are easy to realize on hardware. They found that common tools can add many more steps than necessary, which slows down computations and reduces accuracy. Training a program using QROB’s data helped improve quantum instruction arrangement, and tests on real machines showed better performance and reliability.
quantum compilationquantum circuitsSWAP routingfault-tolerant computinglattice surgeryquantum hardware topologyNISQ (Noisy Intermediate-Scale Quantum)compiler benchmarkingquantum error correctionquantum memory scheduling
Authors
Jintao Li, Kaiqi Li, Rui Wang, Yilun Zhao, Kaixuan Huang, Ying Wang, Jialin Zhang, Zheng-An Wang, Xiaoming Sun, Heng Fan
Abstract
Quantum compilation reconciles a program's idealized interaction topology with hardware locality constraints, yet evaluations at scale lack calibrated references for realization overhead. We present QROB, a scalable reverse-construction methodology that generates compilation instances backward from directly realizable configurations, retaining the inverse paths as feasible, compiler-independent references. QROB provides a common evaluation substrate for NISQ SWAP routing and fault-tolerant lattice-surgery scheduling, while extending its reference-preserving principle to capacity-constrained quantum memory-access scheduling. Across systems ranging from 9 to 156 qubits, evaluations highlight QROB's utility as both a diagnostic benchmark and a data source. First, for compiler characterization, QROB reveals substantial realization gaps in existing tools, with NISQ compilers incurring up to 24.1x the reference SWAP cost and fault-tolerant compilers requiring up to 7.0x the reference makespan. Second, as a supervision source for data-driven compilation, a router trained on QROB references outperforms Qiskit SABRE on 84.8% of real-world application circuits. Finally, on real hardware, QROB reference realizations achieve a median mirror-circuit survival rate 1.65x that of full Qiskit O3 compilations across three 156-qubit IBM Heron-r2 processors, demonstrating that closing algorithmic compilation gaps translates directly into physical fidelity gains.