# Reversible ancilla scheduling ![Reversible ancilla scheduling editorial cover. Illustrative, no experimental data.](docs/figures/cover.gif) **Copyright © 2026 Francisco Angulo de Lafuente. Attribution recorded: 2026-11-06.** **Research author:** [Francisco Angulo de Lafuente](https://orcid.org/0009-0001-1634-7063) · [Citation](CITATION.cff). ## Research question ![Concurrent scratch versus scratch reuse. Partial products; Allocate k scratch; Allocate one scratch; Accumulate all; Add then uncompute; Same accumulator](docs/figures/schedule.gif) *Concurrent scratch versus scratch reuse.* [Static figure](docs/figures/schedule.png). Can scratch registers be reused without increasing Toffoli-like count in a synthetic accumulator? This original experiment is related to the [Google Quantum AI compilation challenge](https://www.kaggle.com/competitions/google-verifiable-quantum-circuit-compilation). It is a local research study, not a contestant circuit, official evaluation or hardware experiment. ## Measured resource counts ![Qubit peak as the number of products increases. Local Kickmix synthetic accumulator, not an official challenge run](docs/figures/qubits.gif) *Qubit peak as the number of products increases.* [Static figure](docs/figures/qubits.png). The recorded Kickmix study uses a 16-bit accumulator. It compares the peak qubit count over five problem sizes. Toffoli-like counts match within each pair, and both circuits produce the expected accumulator for the checked inputs. These fixtures do not establish equivalence for arbitrary quantum states or a challenge score. The raw table is [versioned here](results/recorded_kickmix.json). ## Reproduce and limits ![Check semantic and resource properties separately. Construct circuit; Simulate fixture; Assert accumulator; Read Q and C](docs/figures/verify.gif) *Check semantic and resource properties separately.* [Static figure](docs/figures/verify.png). Run the [experiment](src/measure_kickmix.py) with the separately obtained organizer-compatible Kickmix runtime. The repository does not bundle the verifier, data, other participants' notebooks, or compiled circuits. The recorded run is a controlled comparison of one pattern; it does not imply a better solution for inverse-square-root, DQI, or chemistry tracks. ## License and citation ![Keep the tooling boundary explicit. Original experiment; External Kickmix; Recorded metrics; Project citation](docs/figures/reuse.gif) *Keep the tooling boundary explicit.* [Static figure](docs/figures/reuse.png). The local synthetic experiment source is designated [Apache-2.0](LICENSE) for `src/measure_kickmix.py`; the independent figure renderer is designated [MIT](LICENSE.figures) for `tools/render_lab_figures.py`. See [LICENSE_SCOPE.md](LICENSE_SCOPE.md) for the file-level record. The recorded results, figure specification, cover artwork, generated images, and other documents have separate provenance and license questions; this record makes no new license claim for them. The external Kickmix runtime and organizer verifiers are not bundled. Google's [official announcement](https://opensource.googleblog.com/2026/10/announcing-verifiable-quantum-circuit-compilation-competition-on-kaggle.html) states that the organizer-provided reference circuits and standalone verifiers are Apache-2.0. It does not establish an Apache-2.0 requirement for this separate experiment. The official [Kaggle rules page](https://www.kaggle.com/competitions/google-verifiable-quantum-circuit-compilation/rules) returned no readable text during this review on 2026-11-06, so this repository does not claim verified compliance with every competition-specific sharing term. ## Bibliography and proposed checks - [Bennett (1989), Time/Space Trade-Offs for Reversible Computation](https://doi.org/10.1137/0218053). Compare scratch lifetime and recomputation rather than assuming the cheapest schedule is universal. **Attribution.** Cite [Francisco Angulo de Lafuente](https://orcid.org/0009-0001-1634-7063) using [CITATION.cff](CITATION.cff). Preserve the distinct code notices and consult [LICENSE_SCOPE.md](LICENSE_SCOPE.md) before reusing any other repository material. [License](LICENSE) · [Figure methods and provenance](docs/figures/README.md). **Reuse notice for the original renderer file listed in LICENSE_SCOPE.md:** This project contains open-source material under the MIT License. When redistributing copies or substantial portions, retain the copyright and permission notices. If you build on this work, please cite the project and credit Francisco Angulo de Lafuente (ORCID: 0009-0001-1634-7063). Help advance scientific knowledge: we welcome reproducible results, corrections, and contributions.