{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"53c223146e7dafd77ebb9e3b8932103424d0a52804010b8f0a2688c55e8fd171","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["4b0b1c6e24820c4ae743cb2eb142f30d701b7bbbb0fff87f2bee05b72376ab2f","ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b"],"salt":"e25b12d2d15d795809b5c7cf578af53a9b2e4be6a972ce38df5b1f9f7dedd8eb","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":[],"external_id":"qi.fault-tolerance-noise.exponential-suppression-scaling","kind":"well-posed","literature_status":"open","n":"2","parents":[],"plain":"Recent chips showed that enlarging an error-correcting code cuts the error rate by a constant factor at each step. It is unknown whether this continues to the much larger codes that useful computations need, or whether rare correlated events set a floor.","posed_since":"","precise":"For surface-code memories on superconducting hardware, the logical error per cycle is modeled as $\\epsilon_L(d) \\sim A \\Lambda^{-(d+1)/2}$ with code distance $d$; Google Quantum AI (Nature 638, 920, 2025, arXiv:2408.13687) reported $\\Lambda$ of about 2.1 up to $d = 7$. Determine whether this law holds to $d \\ge 15 \\text{ and } \\epsilon_L \\le 10^{-10}$ per cycle, or whether correlated, leakage or drift events produce a floor; the answer is the measured $\\epsilon_L(d)$ curve or a validated model of its floor.","problem_ref":"4b0b1c6e24820c4ae743cb2eb142f30d701b7bbbb0fff87f2bee05b72376ab2f","references":"","settled_by":"Surface-code memory experiments at $d \\ge 15$ with logical error rates measured down to $10^{-10}$ per cycle, or an identified error mechanism that provably caps suppression.","status_note":"In the same 2025 work, repetition codes up to $d = 29$ reached a logical-error floor near $10^{-10}\\ \\text{per cycle}$ (approximate), set by rare correlated events occurring about once per hour.","title":"Does logical error suppression continue exponentially to large code distance?","topic_ref":null},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"0f3934fbe90d62c96bd66d4d0da3c5a109cb4139ae6efc1e55cb4ae2104b98e3","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"80db4c869a90504e63ce12eea1e2478379c1a961c11764197d195a62a3f95791","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"JzphQFVNA9MzWgPPg5mbLWsBLN-YCdppLLcJp66G6JotbL2Y9v2QiNqeBdl3cOSLuPbK_nTiYjf8ZcpKLuNQDA"},"schema":"pubphys.envelope/1"},"record_hash":"0f3934fbe90d62c96bd66d4d0da3c5a109cb4139ae6efc1e55cb4ae2104b98e3","leaf_index":3708}