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Quantum Interference Needs Convention: Overlap-Determinability and Unified No-Superposition Principle

arXiv Quantum Physics
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⚡ Quantum Brief
Researchers Bang, Cho, and Yee challenge quantum superposition’s practical limits, arguing phase ambiguity in state vectors creates operational barriers for devices attempting to combine unknown pure states coherently. Their study introduces "overlap-determinability," a phase-convention framework proving superposition is only possible when domains fix complex overlaps, unifying prior no-superposition theorems under a single principle. The team’s main theorem establishes an exact equivalence: probabilistic superposition maps exist if and only if the domain is overlap-determinable, with side information supplying missing phase data. Breaking this constraint destabilizes quantum foundations, enabling forbidden operations like cloning, superluminal signaling, and exponential overlap amplification—violating Grover’s search bounds. Computationally, universal access to fixed overlaps collapses query complexity from quadratic to logarithmic, undermining quantum speedup guarantees and redefining information-theoretic limits.
Quantum Interference Needs Convention: Overlap-Determinability and Unified No-Superposition Principle

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Quantum Physics arXiv:2601.14638 (quant-ph) [Submitted on 21 Jan 2026] Title:Quantum Interference Needs Convention: Overlap-Determinability and Unified No-Superposition Principle Authors:Jeongho Bang, Kyoungho Cho, Ki Hyuk Yee View a PDF of the paper titled Quantum Interference Needs Convention: Overlap-Determinability and Unified No-Superposition Principle, by Jeongho Bang and 2 other authors View PDF HTML (experimental) Abstract:Quantum superposition is often phrased as the ability to add state vectors. In practice, however, the physical quantity is a ray (a rank-one projector), so each input specifies only a projector and leaves a gauge freedom in the phases of its vector representatives. This becomes a real operational barrier when one asks for a device that, given two independently prepared unknown pure states, outputs a coherent state proportional to a prescribed linear combination. We identify the missing ingredient as not probabilistic but phase-like. One needs a physical scenario that fixes a single phase convention on the relevant set of rays, so that the overlaps become well defined complex numbers. Thus, we formalize this through phase conventions and a single notion -- dubbed as "overlap-determinability." Our main theorem gives an exact equivalence: A nonzero completely positive trace-nonincreasing map that probabilistically produces superposition on a domain exists if and only if that domain is overlap-determinable. This unifies modern no-superposition results and characterizes the exceptional yes-go protocols, which succeed precisely when side information supplies the required missing resource. We then show that granting universal access to such convention-fixed overlaps destabilizes the familiar foundational and computational constraints. It enables forbidden transformations akin to quantum cloning and yields super-luminal signaling. It would also permit reflections about unknown states, leading to exponentially fast overlap amplification and a collapse of Grover's search lower bound to a logarithmic query complexity. Comments: Subjects: Quantum Physics (quant-ph) Cite as: arXiv:2601.14638 [quant-ph] (or arXiv:2601.14638v1 [quant-ph] for this version) https://doi.org/10.48550/arXiv.2601.14638 Focus to learn more arXiv-issued DOI via DataCite (pending registration) Submission history From: Jeongho Bang [view email] [v1] Wed, 21 Jan 2026 04:25:21 UTC (1,259 KB) Full-text links: Access Paper: View a PDF of the paper titled Quantum Interference Needs Convention: Overlap-Determinability and Unified No-Superposition Principle, by Jeongho Bang and 2 other authorsView PDFHTML (experimental)TeX Source view license Current browse context: quant-ph new | recent | 2026-01 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?) Links to Code Toggle Papers with Code (What is Papers with Code?) 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