{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"3531d59f8967aa87c04723e17a22f523fd2c9764330075e4f8a2438e127bd1a4","created":"2026-10-03T07:18:10Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"58540f0c5d2b64b5c3fd1ca2995bab93aed400ec7a56d7140fa2e57a7e4bce95","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"value","assisted_by":[],"external_id":"qi.qubit-platform-limits.photonic-loss-threshold","kind":"well-posed","literature_status":"open","n":"1","parents":[],"plain":"Photonic quantum computers lose photons in sources, chips and detectors, and their two-photon operations succeed only part of the time. The largest loss rate at which error correction can still work is not known.","posed_since":"","precise":"In fusion-based quantum computation with linear optics, entangled resource states of bounded size are joined by probabilistic two-photon fusion measurements (success probability $1/2$ without ancilla boosting), and each photon is lost with probability $\\eta_L$. Determine the supremum of $\\eta_L$ for which a fault-tolerance threshold exists, as a function of resource-state size and fusion boosting, and decide whether loss tolerance well above the $10.4\\%$ loss per fusion reported for a ballistic scheme by Bartolucci et al. (arXiv:2101.09310, 2021) is reachable with bounded-size resource states.","problem_ref":null,"references":"","settled_by":"An architecture with a computed or proved threshold at higher loss, together with an upper bound on tolerable loss for bounded-size resource states.","status_note":"","title":"Maximum photon loss tolerable in linear-optical fault-tolerant architectures","topic_ref":"c7ae00f823e8ed5856b31a5043e5997ce50764f4156085cbb947e66cdfa20136"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"872e0229614dd573d562deefde53a339af45fbcc79482e64b855f84d9049b257","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"15471d3816658c2c1a964a88fbe614cc64dc1e9df01e0d2943fb5c47defdff2a","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"leiUjSEkth4mRKrh5G4e6NB-BhhkoR_vRPaFFuGi7jRIU_jQ6yfRfOAV_QtJEgnFR6C1W-ridX5gCddpm5vpBw"},"schema":"pubphys.envelope/1"},"record_hash":"872e0229614dd573d562deefde53a339af45fbcc79482e64b855f84d9049b257","leaf_index":2048}