{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2016:66XMCO6MNYGTGCZJVPZOONDTWN","short_pith_number":"pith:66XMCO6M","canonical_record":{"source":{"id":"1603.03974","kind":"arxiv","version":2},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cond-mat.mtrl-sci","submitted_at":"2016-03-13T00:10:55Z","cross_cats_sorted":[],"title_canon_sha256":"bb3ab599a4fb256e42544125a54bd77eacf5053c1d15333a7fb60dbd3064292e","abstract_canon_sha256":"fa557e259fe87044933d4a0a98674e0419cb1bfe0d5ab484b5208d815fdfc92f"},"schema_version":"1.0"},"canonical_sha256":"f7aec13bcc6e0d330b29abf2e73473b37577199b7656eda38c95a90984479172","source":{"kind":"arxiv","id":"1603.03974","version":2},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1603.03974","created_at":"2026-05-18T01:07:16Z"},{"alias_kind":"arxiv_version","alias_value":"1603.03974v2","created_at":"2026-05-18T01:07:16Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1603.03974","created_at":"2026-05-18T01:07:16Z"},{"alias_kind":"pith_short_12","alias_value":"66XMCO6MNYGT","created_at":"2026-05-18T12:30:01Z"},{"alias_kind":"pith_short_16","alias_value":"66XMCO6MNYGTGCZJ","created_at":"2026-05-18T12:30:01Z"},{"alias_kind":"pith_short_8","alias_value":"66XMCO6M","created_at":"2026-05-18T12:30:01Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2016:66XMCO6MNYGTGCZJVPZOONDTWN","target":"record","payload":{"canonical_record":{"source":{"id":"1603.03974","kind":"arxiv","version":2},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cond-mat.mtrl-sci","submitted_at":"2016-03-13T00:10:55Z","cross_cats_sorted":[],"title_canon_sha256":"bb3ab599a4fb256e42544125a54bd77eacf5053c1d15333a7fb60dbd3064292e","abstract_canon_sha256":"fa557e259fe87044933d4a0a98674e0419cb1bfe0d5ab484b5208d815fdfc92f"},"schema_version":"1.0"},"canonical_sha256":"f7aec13bcc6e0d330b29abf2e73473b37577199b7656eda38c95a90984479172","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T01:07:16.995659Z","signature_b64":"zrr5ptXt9SKOriuqoo7V45YFEU04k8PPV0CunQ6gb7xLQS2luMIfYALsFp6939uc98X/VIgZNRv8GPPMu/M1Cw==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"f7aec13bcc6e0d330b29abf2e73473b37577199b7656eda38c95a90984479172","last_reissued_at":"2026-05-18T01:07:16.995031Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T01:07:16.995031Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1603.03974","source_version":2,"attestation_state":"computed"},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-18T01:07:16Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"WqbU0urcZ3DuHgAhrmn1f4D4cKXZ0F68YB7ZCNnWAnOYn2vMlnGsevUObrMuVihRevop5xtOFXRImycfzoPSAA==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-28T01:31:47.330388Z"},"content_sha256":"05ba57b792475c7a9bd6a819bf040001380540905bcb84f1023ef0de9c6a1da8","schema_version":"1.0","event_id":"sha256:05ba57b792475c7a9bd6a819bf040001380540905bcb84f1023ef0de9c6a1da8"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2016:66XMCO6MNYGTGCZJVPZOONDTWN","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"Dirac node lines in pure alkali earth metals","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"cond-mat.mtrl-sci","authors_text":"Dianzhong Li, Hui Ma, Ronghan Li, Shoulong Wang, Xing-Qiu Chen, Xiyue Cheng, Yiyi Li, Zhenyu Zhang","submitted_at":"2016-03-13T00:10:55Z","abstract_excerpt":"Beryllium is a simple alkali earth metal, but has been the target of intensive studies for decades because of its unusual electron behaviors at surfaces. Puzzling aspects include (i) severe deviations from the description of the nearly free electron picture, (ii) anomalously large electron-phonon coupling effect, and (iii) giant Friedal oscillations. The underlying origins for such anomalous surface electron behaviors have been under active debate, but with no consensus. Here, by means of first-principle calculations, we discover that this pure metal system, surprisingly, harbors the Dirac nod"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1603.03974","kind":"arxiv","version":2},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"references":{"count":0,"sample":[],"resolved_work":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57","internal_anchors":0},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"},"verdict_id":null},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-18T01:07:16Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"qyIWOyOW41Icc7xMi1zWQEamDwNA0dTatrK5J2HRBPlyGq6023q9hxo40zg0CIzkt6krBXOetIsB4ypUwlU6AA==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-28T01:31:47.330729Z"},"content_sha256":"21eded664418b74e1e431fe75878904e8fa7fc2347893fc1fe7b1b4f85cb578d","schema_version":"1.0","event_id":"sha256:21eded664418b74e1e431fe75878904e8fa7fc2347893fc1fe7b1b4f85cb578d"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/66XMCO6MNYGTGCZJVPZOONDTWN/bundle.json","state_url":"https://pith.science/pith/66XMCO6MNYGTGCZJVPZOONDTWN/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/66XMCO6MNYGTGCZJVPZOONDTWN/bundle.json","status":"primary"}],"public_keys":[{"key_id":"pith-v1-2026-05","algorithm":"ed25519","format":"raw","public_key_b64":"stVStoiQhXFxp4s2pdzPNoqVNBMojDU/fJ2db5S3CbM=","public_key_hex":"b2d552b68890857171a78b36a5dccf368a953413288c353f7c9d9d6f94b709b3","fingerprint_sha256_b32_first128bits":"RVFV5Z2OI2J3ZUO7ERDEBCYNKS","fingerprint_sha256_hex":"8d4b5ee74e4693bcd1df2446408b0d54","rotates_at":null,"url":"https://pith.science/pith-signing-key.json","notes":"Pith uses this Ed25519 key to sign canonical record SHA-256 digests. Verify with: ed25519_verify(public_key, message=canonical_sha256_bytes, signature=base64decode(signature_b64))."}],"merge_version":"pith-open-graph-merge-v1","built_at":"2026-05-28T01:31:47Z","links":{"resolver":"https://pith.science/pith/66XMCO6MNYGTGCZJVPZOONDTWN","bundle":"https://pith.science/pith/66XMCO6MNYGTGCZJVPZOONDTWN/bundle.json","state":"https://pith.science/pith/66XMCO6MNYGTGCZJVPZOONDTWN/state.json","well_known_bundle":"https://pith.science/.well-known/pith/66XMCO6MNYGTGCZJVPZOONDTWN/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2016:66XMCO6MNYGTGCZJVPZOONDTWN","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":"fa557e259fe87044933d4a0a98674e0419cb1bfe0d5ab484b5208d815fdfc92f","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cond-mat.mtrl-sci","submitted_at":"2016-03-13T00:10:55Z","title_canon_sha256":"bb3ab599a4fb256e42544125a54bd77eacf5053c1d15333a7fb60dbd3064292e"},"schema_version":"1.0","source":{"id":"1603.03974","kind":"arxiv","version":2}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1603.03974","created_at":"2026-05-18T01:07:16Z"},{"alias_kind":"arxiv_version","alias_value":"1603.03974v2","created_at":"2026-05-18T01:07:16Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1603.03974","created_at":"2026-05-18T01:07:16Z"},{"alias_kind":"pith_short_12","alias_value":"66XMCO6MNYGT","created_at":"2026-05-18T12:30:01Z"},{"alias_kind":"pith_short_16","alias_value":"66XMCO6MNYGTGCZJ","created_at":"2026-05-18T12:30:01Z"},{"alias_kind":"pith_short_8","alias_value":"66XMCO6M","created_at":"2026-05-18T12:30:01Z"}],"graph_snapshots":[{"event_id":"sha256:21eded664418b74e1e431fe75878904e8fa7fc2347893fc1fe7b1b4f85cb578d","target":"graph","created_at":"2026-05-18T01:07:16Z","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":"Beryllium is a simple alkali earth metal, but has been the target of intensive studies for decades because of its unusual electron behaviors at surfaces. Puzzling aspects include (i) severe deviations from the description of the nearly free electron picture, (ii) anomalously large electron-phonon coupling effect, and (iii) giant Friedal oscillations. The underlying origins for such anomalous surface electron behaviors have been under active debate, but with no consensus. Here, by means of first-principle calculations, we discover that this pure metal system, surprisingly, harbors the Dirac nod","authors_text":"Dianzhong Li, Hui Ma, Ronghan Li, Shoulong Wang, Xing-Qiu Chen, Xiyue Cheng, Yiyi Li, Zhenyu Zhang","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cond-mat.mtrl-sci","submitted_at":"2016-03-13T00:10:55Z","title":"Dirac node lines in pure alkali earth metals"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1603.03974","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":"sha256:05ba57b792475c7a9bd6a819bf040001380540905bcb84f1023ef0de9c6a1da8","target":"record","created_at":"2026-05-18T01:07:16Z","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":"fa557e259fe87044933d4a0a98674e0419cb1bfe0d5ab484b5208d815fdfc92f","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"cond-mat.mtrl-sci","submitted_at":"2016-03-13T00:10:55Z","title_canon_sha256":"bb3ab599a4fb256e42544125a54bd77eacf5053c1d15333a7fb60dbd3064292e"},"schema_version":"1.0","source":{"id":"1603.03974","kind":"arxiv","version":2}},"canonical_sha256":"f7aec13bcc6e0d330b29abf2e73473b37577199b7656eda38c95a90984479172","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"f7aec13bcc6e0d330b29abf2e73473b37577199b7656eda38c95a90984479172","first_computed_at":"2026-05-18T01:07:16.995031Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T01:07:16.995031Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"zrr5ptXt9SKOriuqoo7V45YFEU04k8PPV0CunQ6gb7xLQS2luMIfYALsFp6939uc98X/VIgZNRv8GPPMu/M1Cw==","signature_status":"signed_v1","signed_at":"2026-05-18T01:07:16.995659Z","signed_message":"canonical_sha256_bytes"},"source_id":"1603.03974","source_kind":"arxiv","source_version":2}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:05ba57b792475c7a9bd6a819bf040001380540905bcb84f1023ef0de9c6a1da8","sha256:21eded664418b74e1e431fe75878904e8fa7fc2347893fc1fe7b1b4f85cb578d"],"state_sha256":"6ecec85daa36c07555e69860ed3a5ae257490dd9216e2849cf7c564bc9d20abe"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"OHEw+QS0x6NwGIEnj1Pe24f/Fxtp5DQagfvC6b2NgLNzFuv+M69O3/m5ECtB3MDL2irnishQKa5Jh+LchdJ+Bw==","signed_message":"bundle_sha256_bytes","signed_at":"2026-05-28T01:31:47.332660Z","bundle_sha256":"23faeb30b2f6dd7caf21e97ae44a7937d1ef6c98689c04d89a6cf7ad7378aea0"}}