Runtime Compilation for Quantum Circuits with PQF-Enabled Rz Synthesis
Abstract
In Fault-Tolerant Quantum Computing (FTQC) using surface codes, reducing T-count is critical for efficient computation due to the high cost of T-state distillation. Probabilistic Quantum Circuit with Fallback (PQF) synthesis significantly lowers T-counts compared to standard protocols like Gridsynth, but introduces high circuit dynamism through extra gates inserted at runtime. This dynamism invalidates static compile-time routing, as these new T gates require dynamic lattice surgery routing to establish non-intersecting ancilla paths to T-state factories while minimizing total execution time. To address this, we introduce R2-PQF, a Runtime Routing protocol for PQF-synthesized quantum circuits. R2-PQF dynamically routes gates layer-by-layer, computing paths during the execution of the previous logical timestep. To satisfy the strict computational window of ∼ tlattice_surgery + treaction and non-intersectionality constraints, we implement a Wavefront Breadth-First Search (W-BFS) and synthesise it on a 500MHz FPGA and 2 GHz ASIC. For a clock cycle of 2GHz, we achieve a median logical time-step of $1.51 μs$ for a 300 qubit Ising Hamiltonian circuit, demonstrating that R2-PQF successfully resolves the vast majority of paths (with rare exceptions) within the execution window and enables the T-count benefits of PQF without latency penalties. Compared to a baseline stalling-based solution (the only no-runtime-recomputation solution), R2-PQF speeds up circuit execution by 1.34× on average and up to 1.76 ×.
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BibTeX
@misc{dangwal2026runtime,
title = {{Runtime Compilation for Quantum Circuits with PQF-Enabled $R_z$ Synthesis}},
author = {Siddharth Dangwal and Christopher Kang and Jad Habhab and Ritvik Sharma and Frederic T. Chong and Gokul Subramanian Ravi},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.04075},
eprint = {2611.04075},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.04075},
}
RIS
TY - UNPB
TI - Runtime Compilation for Quantum Circuits with PQF-Enabled R_z Synthesis
AU - Siddharth Dangwal
AU - Christopher Kang
AU - Jad Habhab
AU - Ritvik Sharma
AU - Frederic T. Chong
AU - Gokul Subramanian Ravi
PY - 2026
DA - 2026/11/02
PB - arXiv
DO - 10.48550/arxiv.2611.04075
UR - https://arxiv.org/abs/2611.04075
AB - In Fault-Tolerant Quantum Computing (FTQC) using surface codes, reducing T-count is critical for efficient computation due to the high cost of T-state distillation. Probabilistic Quantum Circuit with Fallback (PQF) synthesis significantly lowers T-counts compared to standard protocols like Gridsynth, but introduces high circuit dynamism through extra gates inserted at runtime. This dynamism invalidates static compile-time routing, as these new T gates require dynamic lattice surgery routing to establish non-intersecting ancilla paths to T-state factories while minimizing total execution time. To address this, we introduce R^2-PQF, a Runtime Routing protocol for PQF-synthesized quantum circuits. R^2-PQF dynamically routes gates layer-by-layer, computing paths during the execution of the previous logical timestep. To satisfy the strict computational window of ∼ t_lattice_surgery + t_reaction and non-intersectionality constraints, we implement a Wavefront Breadth-First Search (W-BFS) and synthesise it on a 500MHz FPGA and 2 GHz ASIC. For a clock cycle of 2GHz, we achieve a median logical time-step of $1.51 μs$ for a 300 qubit Ising Hamiltonian circuit, demonstrating that R^2-PQF successfully resolves the vast majority of paths (with rare exceptions) within the execution window and enables the T-count benefits of PQF without latency penalties. Compared to a baseline stalling-based solution (the only no-runtime-recomputation solution), R^2-PQF speeds up circuit execution by 1.34× on average and up to 1.76 ×.
ER -