{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2016:MPRSEVH7KACQHANQAIELFL4YJ6","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":"fd6bf3071fed2ef113d85c8559363f87fbd8fe475cb5a8d43be7a16a93ac77db","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"quant-ph","submitted_at":"2016-06-23T08:22:02Z","title_canon_sha256":"93ed1e435bce7e05761105a2241626072dcc99ffadc5385723e6f3f0f1a6b90b"},"schema_version":"1.0","source":{"id":"1606.07220","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1606.07220","created_at":"2026-05-18T01:02:38Z"},{"alias_kind":"arxiv_version","alias_value":"1606.07220v1","created_at":"2026-05-18T01:02:38Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1606.07220","created_at":"2026-05-18T01:02:38Z"},{"alias_kind":"pith_short_12","alias_value":"MPRSEVH7KACQ","created_at":"2026-05-18T12:30:32Z"},{"alias_kind":"pith_short_16","alias_value":"MPRSEVH7KACQHANQ","created_at":"2026-05-18T12:30:32Z"},{"alias_kind":"pith_short_8","alias_value":"MPRSEVH7","created_at":"2026-05-18T12:30:32Z"}],"graph_snapshots":[{"event_id":"sha256:f5c3558a80e1256e6b64910523a7ccdf6d7fa76338382227b0842cec44f77faa","target":"graph","created_at":"2026-05-18T01:02:38Z","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 demonstrate a coherence time of 2.1(1)~s for electron spin superposition states of a single trapped $^{40}$Ca$^+$ ion. The coherence time, measured with a spin-echo experiment, corresponds to residual rms magnetic field fluctuations $\\leq$~2.7$\\times$10$^{-12}$~T. The suppression of decoherence induced by fluctuating magnetic fields is achieved by combining a two-layer $\\mu$-metal shield, which reduces external magnetic noise by 20 to 30~dB for frequencies of 50~Hz to 100~kHz, with Sm$_2$Co$_{17}$ permanent magnets for generating a quantizing magnetic field of 0.37~mT. Our results extend th","authors_text":"Christian T. Schmiegelow, Claudia Warschburger, Ferdinand Schmidt-Kaler, Henning Kaufmann, Thomas Ruster, Ulrich G. Poschinger","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"quant-ph","submitted_at":"2016-06-23T08:22:02Z","title":"A long-lived Zeeman trapped-ion qubit"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1606.07220","kind":"arxiv","version":1},"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":"sha256:03cb3e4e2914108a72b3e2a377a6697960b96e44debc1bcfb3708b4f88248b06","target":"record","created_at":"2026-05-18T01:02:38Z","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":"fd6bf3071fed2ef113d85c8559363f87fbd8fe475cb5a8d43be7a16a93ac77db","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"quant-ph","submitted_at":"2016-06-23T08:22:02Z","title_canon_sha256":"93ed1e435bce7e05761105a2241626072dcc99ffadc5385723e6f3f0f1a6b90b"},"schema_version":"1.0","source":{"id":"1606.07220","kind":"arxiv","version":1}},"canonical_sha256":"63e32254ff50050381b00208b2af984fbf4c9c8163f519fd97298460eed9eeca","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"63e32254ff50050381b00208b2af984fbf4c9c8163f519fd97298460eed9eeca","first_computed_at":"2026-05-18T01:02:38.674830Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T01:02:38.674830Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"gPQzi3dgFhsCBHmwBO9WE40zFEyVDdVxe/i+3PthRDRIC9O1uumArWMKorCIsAC/hmrzdGDOcFIpPYVYsC23Bw==","signature_status":"signed_v1","signed_at":"2026-05-18T01:02:38.675549Z","signed_message":"canonical_sha256_bytes"},"source_id":"1606.07220","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:03cb3e4e2914108a72b3e2a377a6697960b96e44debc1bcfb3708b4f88248b06","sha256:f5c3558a80e1256e6b64910523a7ccdf6d7fa76338382227b0842cec44f77faa"],"state_sha256":"13bc0fd0c294777c023d68f7391f8be78142af063c770c5e7fb684a1daaeb9a1"}