{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"0c5c77710dd5112db51e2bd6d112b50bb2608aec8bdcc7ca79648f29253ef4c8","created":"2026-10-03T07:18:10Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"5f14d00da7eeec7c208d0f8d4bcf759c593ad1f52d11fe34f38c922c9a422f25","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"identification","assisted_by":[],"external_id":"qi.tunneling-arrival-time.arrival-time-distribution","kind":"well-posed","literature_status":"contested","n":"1","parents":[],"plain":"Quantum mechanics predicts where a particle will be found but has no single rule for when it reaches a detector. Competing rules give different predictions, notably for particles with spin, which an experiment could compare.","posed_since":"","precise":"For a free particle of spin 0 or 1/2 with initial wave packet $\\psi_0$ and an ideal detector surface at distance $L$, determine the distribution of detection times, comparing the quantum flux $J(L,t)$, the Kijowski distribution, Bohmian predictions including the spin term of the Pauli current (Das and Durr, Scientific Reports 2019), and absorbing-boundary models. An answer is a derivation from detector models that singles one out, or an experiment resolving their differences.","problem_ref":null,"references":"","settled_by":"A time-of-flight experiment with spin-polarized cold atoms or electrons in a waveguide resolving the predicted differences, supported by a detector model.","status_note":"Goldstein, Tumulka and Zanghi (arXiv:2309.11835, 2023) argued the Das-Durr spin effect is not measurable as an arrival time, which a 2023 comment (arXiv:2312.01802) disputes.","title":"What is the arrival-time distribution of a free quantum particle?","topic_ref":"358768349f8fe9b49e5942c4fef2bbf2a089805f474e2a5f2d52d216a641711f"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"512ff0c0ef5c94000c6f24a857c76f3c07a7bc5b8a97063b5d9f794e7a53e311","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"16f5e38fdaeafc2ca5337812cd5ac5327c0ca245258db928087d3f0fe6c5d0cf","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"bx-BKe_qEPTjN_7jp879dbWR72xB9-zarrMO_F-bSwk1iS9M59IS5aLmwaYOX9Ow0Fbss1KrvZkBWjH3hGfJCA"},"schema":"pubphys.envelope/1"},"record_hash":"512ff0c0ef5c94000c6f24a857c76f3c07a7bc5b8a97063b5d9f794e7a53e311","leaf_index":2057}