{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"85960e7589f191ca48a61ac1e52cff49b5269fe6eb36f3a72abf5c74f72dfa9e","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["67970e05fa2517e37711f2e1031983854a9bb1c7829696e1161a67c41bbd07c0","ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b"],"salt":"ba3956c59ed6e507bb91c972437290bb86b253c873cbccf40862f8dc7f803f90","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":"2","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":"67970e05fa2517e37711f2e1031983854a9bb1c7829696e1161a67c41bbd07c0","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":null},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"f6dda8cafeae1f25c6a9cac7d39e78c260d02226a525443a1c89b12f3677e9b0","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"acfb248b48455349460e50e659cde2e97e1ce427866a8239d0d80ea85fab3b15","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"joXB2OkzSrQAGBXdqILpp98zTApA2Ib_IkZQ77O5PKQXBgeHhXlJ7RV4u_uBBClGsg2GsTcnKB8tXNGL94qqAA"},"schema":"pubphys.envelope/1"},"record_hash":"f6dda8cafeae1f25c6a9cac7d39e78c260d02226a525443a1c89b12f3677e9b0","leaf_index":3018}