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Coherent Rollout Oracles for Finite-Horizon Sequential Decision Problems

arXiv Quantum Physics
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⚡ Quantum Brief
Nishant Shukla introduces the first reversible-circuit complexity analysis for coherent rank-select, a quantum primitive enabling reversible action selection in sequential decision problems under branch-dependent constraints. The work proves gate-optimal constructions: an O(Nw)-gate low-ancilla scan (optimal in bounded-span models) and an O(N log w)-gate blocked variant when long-range gates are available, with an Ω(N) unconditional lower bound. A polynomial-size coherent rollout oracle emerges by combining rank-select with reversible transition circuits, offering quantum speedups for finite-horizon planning problems like epidemic intervention. The oracle achieves Õ(√k/ε) coherent calls versus classical Ω(k/ε²) arm-pull bounds, leveraging Wang et al.’s best-arm pipeline framework for exponential query efficiency gains. Results are formally verified in Lean 4, with applications demonstrated in SIR epidemic models and stochastic games, extending to exponential configuration families via a bounded-influence lifting theorem.
Coherent Rollout Oracles for Finite-Horizon Sequential Decision Problems

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Quantum Physics arXiv:2604.25962 (quant-ph) [Submitted on 28 Apr 2026] Title:Coherent Rollout Oracles for Finite-Horizon Sequential Decision Problems Authors:Nishant Shukla View a PDF of the paper titled Coherent Rollout Oracles for Finite-Horizon Sequential Decision Problems, by Nishant Shukla View PDF HTML (experimental) Abstract:Coherent quantum rollout for sequential decision problems requires a unitary simulator: randomness must live in explicit quantum registers, and basis-state selectors must be mapped to actions reversibly. With branch-dependent valid actions, this mapping is totalized coherent rank-select over an entangled $N$-bit validity mask: return the position of the $r$-th valid bit, or a sentinel if $r$ is out of range. We give the first reversible-circuit complexity analysis of this primitive. For selector width $w = \lceil \log_2(N+1) \rceil$, rank-select admits an $O(Nw)$-gate low-ancilla bounded-span scan, proved gate-optimal in its model, and an $O(N\log w)$-gate low-ancilla blocked construction when long-range gates are available; across all bounded-fan-in layouts, the unconditional gate lower bound is $\Omega(N)$. Composing rank-select with reversible transition and predicate-evaluation circuits gives an explicit polynomial-size coherent rollout oracle for finite-horizon planning problems satisfying these primitive assumptions. The resulting oracle satisfies the access model of the best-arm pipeline of Wang et al., yielding $\widetilde{O}(\sqrt{k}/\varepsilon)$ coherent oracle calls against the standard classical $\Omega(k/\varepsilon^2)$ arm-pull lower bound. We give a bounded-influence lifting theorem that extends this lower-bound construction from a base configuration to an exponential family of configurations. We instantiate the construction on SIR epidemic intervention, with a stochastic placement-game sanity check, and machine-check the main results in Lean 4. Code and proofs: this https URL. Comments: Subjects: Quantum Physics (quant-ph); Data Structures and Algorithms (cs.DS) Cite as: arXiv:2604.25962 [quant-ph] (or arXiv:2604.25962v1 [quant-ph] for this version) https://doi.org/10.48550/arXiv.2604.25962 Focus to learn more arXiv-issued DOI via DataCite (pending registration) Submission history From: Nishant Shukla [view email] [v1] Tue, 28 Apr 2026 00:46:37 UTC (111 KB) Full-text links: Access Paper: View a PDF of the paper titled Coherent Rollout Oracles for Finite-Horizon Sequential Decision Problems, by Nishant ShuklaView PDFHTML (experimental)TeX Source view license Current browse context: quant-ph new | recent | 2026-04 Change to browse by: cs cs.DS References & Citations INSPIRE HEP NASA ADSGoogle Scholar Semantic Scholar export BibTeX citation Loading... BibTeX formatted citation × loading... Data provided by: Bookmark Bibliographic Tools Bibliographic and Citation Tools Bibliographic Explorer Toggle Bibliographic Explorer (What is the Explorer?) Connected Papers Toggle Connected Papers (What is Connected Papers?) Litmaps Toggle Litmaps (What is Litmaps?) scite.ai Toggle scite Smart Citations (What are Smart Citations?) Code, Data, Media Code, Data and Media Associated with this Article alphaXiv Toggle alphaXiv (What is alphaXiv?) Links to Code Toggle CatalyzeX Code Finder for Papers (What is CatalyzeX?) DagsHub Toggle DagsHub (What is DagsHub?) GotitPub Toggle Gotit.pub (What is GotitPub?) Huggingface Toggle Hugging Face (What is Huggingface?) ScienceCast Toggle ScienceCast (What is ScienceCast?) Demos Demos Replicate Toggle Replicate (What is Replicate?) Spaces Toggle Hugging Face Spaces (What is Spaces?) Spaces Toggle TXYZ.AI (What is TXYZ.AI?) Related Papers Recommenders and Search Tools Link to Influence Flower Influence Flower (What are Influence Flowers?) Core recommender toggle CORE Recommender (What is CORE?) Author Venue Institution Topic About arXivLabs arXivLabs: experimental projects with community collaborators arXivLabs is a framework that allows collaborators to develop and share new arXiv features directly on our website. Both individuals and organizations that work with arXivLabs have embraced and accepted our values of openness, community, excellence, and user data privacy. arXiv is committed to these values and only works with partners that adhere to them. Have an idea for a project that will add value for arXiv's community? Learn more about arXivLabs. Which authors of this paper are endorsers? | Disable MathJax (What is MathJax?)

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Source: arXiv Quantum Physics