Coherence-gated quantum devices via real-time weak measurement
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Quantum Physics arXiv:2604.18662 (quant-ph) [Submitted on 20 Apr 2026] Title:Coherence-gated quantum devices via real-time weak measurement Authors:Priyank Singh View a PDF of the paper titled Coherence-gated quantum devices via real-time weak measurement, by Priyank Singh View PDF HTML (experimental) Abstract:Single-photon routers in cavity and circuit QED direct photons based on which energy eigenstate a qubit occupies -- a projective decision that destroys coherence. We propose \emph{coherence-gated routing}, where the routing decision depends on the magnitude of quantum coherence, estimated in real time from simultaneous weak measurements of $\sigma_x$ and $\sigma_z$. A photon is accepted depending on whether $S(T) = \sqrt{\langle\sigma_x\rangle_c^2 + \langle\sigma_y\rangle_c^2}$ exceeds a tunable threshold~$S_{\mathrm{th}}$. Because coherence is certified at emission, the protocol enables two applications beyond conventional heralded sources: (i)~a quantum random number generator with min-entropy bounded by Bloch-sphere geometry, $H_\infty \geq -\log_2\bigl(\frac{1+\sqrt{1-S_{\mathrm{th}}^2}}{2}\bigr)$, and (ii)~a phase-tracked photon source where independent certification at two nodes bounds the matter-matter entanglement fidelity after Bell-state measurement. The real-time estimator is a security primitive, not merely a numerical tool. We benchmark seven configurations across 3000 trajectories and show that deliberately underestimating detector efficiency ($\eta_{\mathrm{a}} new | recent | 2026-04 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?)