{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"6b3fa693ef75bc5367fc5db4516e2733ffd61e50aecb0205ed4260c394314ec9","created":"2026-10-03T07:18:01Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["5475cf5dc5b1a72283d26dc95dc6e00d7ea4e00096a7c6492e409a1816eeb011"],"salt":"80c70bc63f40f356b356b279d998c31db2595bbdc7556f9d0b6462cd4d4d8880","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"mechanism","assisted_by":[],"external_id":"cm.scars-fragmentation.pxp-revival-origin","kind":"phenomenon","literature_status":"open","n":"1","parents":[],"plain":"In chains of Rydberg atoms where neighbours cannot both be excited, one special initial pattern keeps returning to itself instead of thermalizing. The underlying reason is not fully understood.","posed_since":"2017","precise":"In the PXP model $H = \\Omega \\sum_i P_{i-1} X_i P_{i+1}$ (P the projector onto the atomic ground state, X the Pauli flip), the period-2 density-wave $(\\mathrm{Z2})$ state shows revivals carried by a tower of special eigenstates with nearly equal energy spacing. Explain the origin of this tower (broken $\\operatorname{su}(2)$ algebra, semiclassical periodic orbit, or proximity to an integrable point) in a form that predicts the revival frequency and decay rate. Answer: a theory with quantitative predictions for both.","problem_ref":null,"references":"","settled_by":"A derivation predicting revival frequency and damping to within a few percent, tested against numerics at $L \\ge 30$.","status_note":"","title":"Why the Rydberg-blockade chain shows persistent revivals","topic_ref":"3b1e0e154649f2c57946e34060cf2af98d1b7646f80dd79c46fd50757079bd2a"},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"dc9feea9191c508db3c7ccef35d39591c4b67eb8f26ff9370cf73c25b3c79258","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"82e9350edabc4ec98cc7dedc38e14464f0fdc4301db324bedee21f78b8f22554","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"OURaRq1MEzY7wvCSRsyb_1nEU_7tdd5aRq-YwZ-PBN8mP76IpkM8AANEb5MeyfgIIwT3aFShqDCqe7iICGvtBw"},"schema":"pubphys.envelope/1"},"record_hash":"dc9feea9191c508db3c7ccef35d39591c4b67eb8f26ff9370cf73c25b3c79258","leaf_index":1148}