{"paper":{"title":"Coherence-gated quantum devices via real-time weak measurement","license":"http://creativecommons.org/licenses/by/4.0/","headline":"Quantum routers can gate photon acceptance on real-time coherence estimates from weak measurements without destroying coherence.","cross_cats":[],"primary_cat":"quant-ph","authors_text":"Priyank Singh","submitted_at":"2026-04-20T12:19:54Z","abstract_excerpt":"Single-photon routers in cavity and circuit QED direct photons by the qubit's energy eigenstate -- a projective decision that destroys coherence. We propose a different primitive: coherence-gated routing, where the decision depends on the magnitude of the qubit's quantum coherence, estimated in real time from simultaneous weak measurements of $\\sigma_x$ and $\\sigma_z$. A photon is accepted if the coherence score $S(T) = \\sqrt{\\langle\\sigma_x\\rangle_c^2 + \\langle\\sigma_y\\rangle_c^2}$, extracted from the conditional density matrix via the stochastic master equation, exceeds a tunable threshold $"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"A photon is accepted depending on whether S(T) = sqrt(<σ_x>_c² + <σ_y>_c²) exceeds a tunable threshold S_th. This enables a quantum random number generator with min-entropy bounded by Bloch-sphere geometry, H_∞ ≥ -log₂((1 + sqrt(1 - S_th²))/2), and a phase-tracked photon source where independent certification at two nodes bounds the matter-matter entanglement fidelity after Bell-state measurement.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"That the real-time coherence estimator computed from simultaneous weak measurements of σ_x and σ_z remains a faithful lower bound on actual coherence even after the deliberate underestimation of detector efficiency η_a, and that the purity monotonicity result invoked to control overcertification holds under the experimental noise model.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"Coherence-gated routing accepts photons when real-time weak-measurement coherence estimate S(T) exceeds a threshold, yielding geometrically bounded min-entropy for QRNG and fidelity bounds for entanglement.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"Quantum routers can gate photon acceptance on real-time coherence estimates from weak measurements without destroying coherence.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"00858230c26341779c2005b2e47e3e8de00da9aee56e5726bb26f6bb7e2830ac"},"source":{"id":"2604.18662","kind":"arxiv","version":2},"verdict":{"id":"a3e50ba6-bd7b-41ea-8fbf-db14a392223a","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-10T05:03:00.384365Z","strongest_claim":"A photon is accepted depending on whether S(T) = sqrt(<σ_x>_c² + <σ_y>_c²) exceeds a tunable threshold S_th. This enables a quantum random number generator with min-entropy bounded by Bloch-sphere geometry, H_∞ ≥ -log₂((1 + sqrt(1 - S_th²))/2), and a phase-tracked photon source where independent certification at two nodes bounds the matter-matter entanglement fidelity after Bell-state measurement.","one_line_summary":"Coherence-gated routing accepts photons when real-time weak-measurement coherence estimate S(T) exceeds a threshold, yielding geometrically bounded min-entropy for QRNG and fidelity bounds for entanglement.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"That the real-time coherence estimator computed from simultaneous weak measurements of σ_x and σ_z remains a faithful lower bound on actual coherence even after the deliberate underestimation of detector efficiency η_a, and that the purity monotonicity result invoked to control overcertification holds under the experimental noise model.","pith_extraction_headline":"Quantum routers can gate photon acceptance on real-time coherence estimates from weak measurements without destroying coherence."},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2604.18662/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}