{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"85ea356793987f20dd69371c25567a20107097d05306f18beb3936a01a0274fc","created":"2026-10-03T07:18:01Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"abb4432c912bd178d490f9cee1645ff07b1841a08119bd5c4281e2dfe282925d","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"yes-no","assisted_by":[],"external_id":"cm.scars-fragmentation.pxp-thermodynamic-limit","kind":"well-posed","literature_status":"open","n":"1","parents":[],"plain":"The special non-thermal states have been seen only in chains of a few dozen atoms. It is unknown whether they remain special in an infinitely long chain.","posed_since":"","precise":"In the PXP chain, define the fidelity density $f(t) = -\\lim_{L \\to \\infty} (1/L) \\ln \\mid\\langle \\mathrm{Z2}\\mid \\exp(-i H t/\\hbar) \\mid\\mathrm{Z2}\\rangle\\mid^{2}$. Is $f$ at the first revival time strictly smaller than its time-averaged plateau value as $L \\to \\infty$? And does a tower of about $L+1$ eigenstates with entanglement $S = O(\\ln L)$ and Z2 overlap exceeding that of typical eigenstates at the same energy by a factor $\\exp(+a L), a > 0$, persist? Answer yes or no for each.","problem_ref":null,"references":"","settled_by":"An exact construction of the scar tower at all L, or infinite-system tensor-network computation of f(t) showing convergence of the revival dip with bond dimension.","status_note":"","title":"Do PXP scar eigenstates survive as the chain becomes infinite","topic_ref":"3b1e0e154649f2c57946e34060cf2af98d1b7646f80dd79c46fd50757079bd2a"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"67970e05fa2517e37711f2e1031983854a9bb1c7829696e1161a67c41bbd07c0","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"eb50018a239a10c53d7d033687dcb980ab5d47c48ac68200db5bd6b06a319b4d","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"A2SNymvZ9ywL4-lB_VaVQA8KOg8Rxz49biwDFO4vjQSPR90H43JGrqHgWqpWydE_K8JEws-MLQG1DTrYtWhADw"},"schema":"pubphys.envelope/1"},"record_hash":"67970e05fa2517e37711f2e1031983854a9bb1c7829696e1161a67c41bbd07c0","leaf_index":1149}