Modular Compilation for Quantum Chiplet Architectures

Abstract: As quantum computing technology matures, industry is adopting modular quantum architectures to keep quantum scaling on the projected path and meet performance targets. However, the complexity of chiplet-based quantum devices, coupled with their growing size, presents an imminent scalability challenge for quantum compilation. Contemporary compilation methods are not well-suited to chiplet architectures - in particular, existing qubit allocation methods are often unable to contend with inter-chiplet links, which don't necessarily support a universal basis gate set. Furthermore, existing methods of logical-to-physical qubit placement, swap insertion (routing), unitary synthesis, and/or optimization, are typically not designed for qubit links of significantly varying latency or fidelity. In this work, we propose SEQC, a hierarchical parallelized compilation pipeline optimized for chiplet-based quantum systems, including several novel methods for qubit placement, qubit routing, and circuit optimization. SEQC attains a $9.3\%$ average increase in circuit fidelity (up to $49.99\%$). Additionally, owing to its ability to parallelize compilation, SEQC achieves $3.27\times$ faster compilation on average (up to $6.74\times$) over a chiplet-unaware Qiskit baseline.