{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2018:CV4KP5GIYEEMAYTOMKMP47KHF5","merge_version":"pith-open-graph-merge-v1","event_count":2,"valid_event_count":2,"invalid_event_count":0,"equivocation_count":0,"current":{"canonical_record":{"metadata":{"abstract_canon_sha256":"c4f3a0ae2d64ba8ba6ab9b501540bfcd7799324d76c7619c7a8cc1ee5afad4f4","cross_cats_sorted":["physics.atom-ph","quant-ph"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cond-mat.quant-gas","submitted_at":"2018-05-12T14:31:54Z","title_canon_sha256":"3811f7d232c66ac403baafafbc8c87b0ed73f9f5298241e22629eed389085053"},"schema_version":"1.0","source":{"id":"1805.04727","kind":"arxiv","version":2}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1805.04727","created_at":"2026-05-18T00:09:52Z"},{"alias_kind":"arxiv_version","alias_value":"1805.04727v2","created_at":"2026-05-18T00:09:52Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1805.04727","created_at":"2026-05-18T00:09:52Z"},{"alias_kind":"pith_short_12","alias_value":"CV4KP5GIYEEM","created_at":"2026-05-18T12:32:19Z"},{"alias_kind":"pith_short_16","alias_value":"CV4KP5GIYEEMAYTO","created_at":"2026-05-18T12:32:19Z"},{"alias_kind":"pith_short_8","alias_value":"CV4KP5GI","created_at":"2026-05-18T12:32:19Z"}],"graph_snapshots":[{"event_id":"sha256:befac6dac72a96f5d51f4339d14ca6cf9aca0eb013679387d177501a409972e2","target":"graph","created_at":"2026-05-18T00:09:52Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"graph_snapshot":{"author_claims":{"count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","strong_count":0},"builder_version":"pith-number-builder-2026-05-17-v1","claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"paper":{"abstract_excerpt":"We report the observation of parametric down-conversion of phonons in a spherical Bose-Einstein condensate. The spherical symmetry, which is crucial for observing this phenomenon, is experimentally demonstrated by measuring the collective mode and expansion behavior of the condensate. The low-energy monopole mode is excited by coupling with a high-energy mode with a nearly twice eigen-frequency. The population of the low-energy mode becomes maximum only when the high-energy mode is resonantly excited. Furthermore, we directly observe the parametric down-conversion process in the driving proces","authors_text":"Dongfang Zhang, Jian-Song Pan, Kaijun Jiang, Lingran Kong, Mingsheng Zhan, Ruizong Li, Shi-Guo Peng, Tianyou Gao, W. Vincent Liu, Xiaolong Chen, Xing Shen","cross_cats":["physics.atom-ph","quant-ph"],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cond-mat.quant-gas","submitted_at":"2018-05-12T14:31:54Z","title":"Observation of phonon parametric down-conversion in a spherical Bose-Einstein condensate"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1805.04727","kind":"arxiv","version":2},"verdict":{"created_at":null,"id":null,"model_set":{},"one_line_summary":"","pipeline_version":null,"pith_extraction_headline":"","strongest_claim":"","weakest_assumption":""}},"verdict_id":null}}],"author_attestations":[],"timestamp_anchors":[],"storage_attestations":[],"citation_signatures":[],"replication_records":[],"corrections":[],"mirror_hints":[],"record_created":{"event_id":"sha256:b184031f9b45e2c38c2997eaa7ecb2acb623ae44b7ac472e56d9da0a0e048b22","target":"record","created_at":"2026-05-18T00:09:52Z","signer":{"key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signer_id":"pith.science","signer_type":"pith_registry"},"payload":{"attestation_state":"computed","canonical_record":{"metadata":{"abstract_canon_sha256":"c4f3a0ae2d64ba8ba6ab9b501540bfcd7799324d76c7619c7a8cc1ee5afad4f4","cross_cats_sorted":["physics.atom-ph","quant-ph"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cond-mat.quant-gas","submitted_at":"2018-05-12T14:31:54Z","title_canon_sha256":"3811f7d232c66ac403baafafbc8c87b0ed73f9f5298241e22629eed389085053"},"schema_version":"1.0","source":{"id":"1805.04727","kind":"arxiv","version":2}},"canonical_sha256":"1578a7f4c8c108c0626e6298fe7d472f7af81e496cb6b8475920da9e3a83ba9d","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"1578a7f4c8c108c0626e6298fe7d472f7af81e496cb6b8475920da9e3a83ba9d","first_computed_at":"2026-05-18T00:09:52.272416Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T00:09:52.272416Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"R3x4rIws2sbmWvy0et44G18ZYm4XlYiqc+tzlfBqL67lnGHu5JgiVk2bVmhsRohzwV50/pwK1bHwX3QezotrAQ==","signature_status":"signed_v1","signed_at":"2026-05-18T00:09:52.273059Z","signed_message":"canonical_sha256_bytes"},"source_id":"1805.04727","source_kind":"arxiv","source_version":2}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:b184031f9b45e2c38c2997eaa7ecb2acb623ae44b7ac472e56d9da0a0e048b22","sha256:befac6dac72a96f5d51f4339d14ca6cf9aca0eb013679387d177501a409972e2"],"state_sha256":"706cf57e01798a957a55a8e6ceece31f0c1de2bb222822691d1821d511718656"}