{"paper":{"title":"Polarization, Maximal Concurrence, and Pure States in High-Energy Collisions","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"Increasing local spin polarization imposes an upper bound on concurrence in two-qubit systems.","cross_cats":["hep-ex","nucl-th","quant-ph"],"primary_cat":"hep-ph","authors_text":"Bo-Wen Xiao, Luo-Ting He, Wei Qi, Yu-Xuan Liu","submitted_at":"2026-04-20T03:17:43Z","abstract_excerpt":"We establish a quantitative relation between local spin polarization and quantum entanglement in two-qubit systems by deriving an upper bound on the concurrence at fixed local polarizations, showing that increasing polarization constrains the maximum achievable entanglement. We further demonstrate that this bound is saturated by pure states in certain cases with identical polarizations. As a concrete physical application, we consider the parity-violating process $e^+e^- \\to Z^0 \\to q\\bar{q}$, which generates final-state spin polarization. We show that the maximal concurrence is attained in spe"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"We establish a quantitative relation between local spin polarization and quantum entanglement in two-qubit systems by deriving an upper bound on the concurrence at fixed local polarization, showing that increasing polarization constrains the maximum achievable entanglement. We further demonstrate that this bound is saturated by pure states in certain cases.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"The assumption that the spin degrees of freedom of the final-state quarks in e+e- to Z to qqbar can be faithfully modeled as a two-qubit system with a well-defined local polarization vector that directly enters the concurrence bound.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"Local spin polarization imposes an upper bound on concurrence in two-qubit systems that is saturated by pure states, and this bound lowers maximal entanglement in the polarized e+e- to Z to qqbar process relative to the unpolarized case.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"Increasing local spin polarization imposes an upper bound on concurrence in two-qubit systems.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"e2776cb16d9eccfb484732e4864ab473e6aae5db736d10e24df13518167f1e5e"},"source":{"id":"2604.17756","kind":"arxiv","version":2},"verdict":{"id":"f9119e34-e26f-485f-8666-77af88a51a40","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-10T05:11:42.217226Z","strongest_claim":"We establish a quantitative relation between local spin polarization and quantum entanglement in two-qubit systems by deriving an upper bound on the concurrence at fixed local polarization, showing that increasing polarization constrains the maximum achievable entanglement. We further demonstrate that this bound is saturated by pure states in certain cases.","one_line_summary":"Local spin polarization imposes an upper bound on concurrence in two-qubit systems that is saturated by pure states, and this bound lowers maximal entanglement in the polarized e+e- to Z to qqbar process relative to the unpolarized case.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"The assumption that the spin degrees of freedom of the final-state quarks in e+e- to Z to qqbar can be faithfully modeled as a two-qubit system with a well-defined local polarization vector that directly enters the concurrence bound.","pith_extraction_headline":"Increasing local spin polarization imposes an upper bound on concurrence in two-qubit systems."},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2604.17756/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"}