{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2019:7URMXWHTH533JITEXGBXEZWULL","short_pith_number":"pith:7URMXWHT","canonical_record":{"source":{"id":"1901.09416","kind":"arxiv","version":2},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"hep-th","submitted_at":"2019-01-27T18:25:56Z","cross_cats_sorted":["hep-ph"],"title_canon_sha256":"3d48754e3cc3cdc5076f7181dfcfb25d7c21006b06e23176a58105d1ccb5acb3","abstract_canon_sha256":"5800678fb5dca6ca12b8abec0e40eca81a60b152a0bafa4b2c07317a02d6ff1d"},"schema_version":"1.0"},"canonical_sha256":"fd22cbd8f33f77b4a264b9837266d45af64f680bb1de999cda2d6052a7e287b0","source":{"kind":"arxiv","id":"1901.09416","version":2},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1901.09416","created_at":"2026-05-17T23:46:29Z"},{"alias_kind":"arxiv_version","alias_value":"1901.09416v2","created_at":"2026-05-17T23:46:29Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1901.09416","created_at":"2026-05-17T23:46:29Z"},{"alias_kind":"pith_short_12","alias_value":"7URMXWHTH533","created_at":"2026-05-18T12:33:12Z"},{"alias_kind":"pith_short_16","alias_value":"7URMXWHTH533JITE","created_at":"2026-05-18T12:33:12Z"},{"alias_kind":"pith_short_8","alias_value":"7URMXWHT","created_at":"2026-05-18T12:33:12Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2019:7URMXWHTH533JITEXGBXEZWULL","target":"record","payload":{"canonical_record":{"source":{"id":"1901.09416","kind":"arxiv","version":2},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"hep-th","submitted_at":"2019-01-27T18:25:56Z","cross_cats_sorted":["hep-ph"],"title_canon_sha256":"3d48754e3cc3cdc5076f7181dfcfb25d7c21006b06e23176a58105d1ccb5acb3","abstract_canon_sha256":"5800678fb5dca6ca12b8abec0e40eca81a60b152a0bafa4b2c07317a02d6ff1d"},"schema_version":"1.0"},"canonical_sha256":"fd22cbd8f33f77b4a264b9837266d45af64f680bb1de999cda2d6052a7e287b0","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-17T23:46:29.048808Z","signature_b64":"ik04UpPDxFzoIKfw+fcW77eWSTIomKzYAIhbLIA3yMoeqXvU7qqQjqn6tz8wKYs2wvuWsIeEWIeblLMX7m3dCg==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"fd22cbd8f33f77b4a264b9837266d45af64f680bb1de999cda2d6052a7e287b0","last_reissued_at":"2026-05-17T23:46:29.048163Z","signature_status":"signed_v1","first_computed_at":"2026-05-17T23:46:29.048163Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1901.09416","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":"2026-05-17T23:46:29Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"vJUWNJaseuesbUN408RDnXCmoG7OGrkyjv13/+CGrYUHAme7zCPcixzp/DsBUBm04sLxch2HSOxu/hVCJghyDg==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-25T19:55:59.194210Z"},"content_sha256":"01d25915d19b19289321e3e57a98879146c08618a8a2af9c8c7eece0ad3e9142","schema_version":"1.0","event_id":"sha256:01d25915d19b19289321e3e57a98879146c08618a8a2af9c8c7eece0ad3e9142"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2019:7URMXWHTH533JITEXGBXEZWULL","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"Reducible contributions to quantum electrodynamics in external fields","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":["hep-ph"],"primary_cat":"hep-th","authors_text":"Anton Ilderton, James P. Edwards, Naser Ahmadiniaz","submitted_at":"2019-01-27T18:25:56Z","abstract_excerpt":"We consider one-particle reducible (1PR) contributions to QED and scalar QED processes in external fields, at one-loop and two-loop order. We investigate three cases in detail: constant crossed fields, constant magnetic fields, and plane waves. We find that 1PR tadpole contributions in plane waves and constant crossed fields are non-zero, but contribute only divergences to be renormalised away. In constant magnetic fields, on the other hand, tadpole contributions give physical corrections to processes at one-loop and beyond. Our calculations are exact in the external fields and we give strong "},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1901.09416","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":"2026-05-17T23:46:29Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"5CDQz1G1/z3KwAbUrdQGa6YYEREfgXxu5i7jffRoTlCYwLQlXpPbEHluSgzSCxTy8w5NTZYZdZcj1P3FIOCwCA==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-25T19:55:59.194616Z"},"content_sha256":"4321714c460d81d03923fd066073fac9afba004aeea3eb57128217b852027b0c","schema_version":"1.0","event_id":"sha256:4321714c460d81d03923fd066073fac9afba004aeea3eb57128217b852027b0c"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/7URMXWHTH533JITEXGBXEZWULL/bundle.json","state_url":"https://pith.science/pith/7URMXWHTH533JITEXGBXEZWULL/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/7URMXWHTH533JITEXGBXEZWULL/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":"2026-05-25T19:55:59Z","links":{"resolver":"https://pith.science/pith/7URMXWHTH533JITEXGBXEZWULL","bundle":"https://pith.science/pith/7URMXWHTH533JITEXGBXEZWULL/bundle.json","state":"https://pith.science/pith/7URMXWHTH533JITEXGBXEZWULL/state.json","well_known_bundle":"https://pith.science/.well-known/pith/7URMXWHTH533JITEXGBXEZWULL/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2019:7URMXWHTH533JITEXGBXEZWULL","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":"5800678fb5dca6ca12b8abec0e40eca81a60b152a0bafa4b2c07317a02d6ff1d","cross_cats_sorted":["hep-ph"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"hep-th","submitted_at":"2019-01-27T18:25:56Z","title_canon_sha256":"3d48754e3cc3cdc5076f7181dfcfb25d7c21006b06e23176a58105d1ccb5acb3"},"schema_version":"1.0","source":{"id":"1901.09416","kind":"arxiv","version":2}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1901.09416","created_at":"2026-05-17T23:46:29Z"},{"alias_kind":"arxiv_version","alias_value":"1901.09416v2","created_at":"2026-05-17T23:46:29Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1901.09416","created_at":"2026-05-17T23:46:29Z"},{"alias_kind":"pith_short_12","alias_value":"7URMXWHTH533","created_at":"2026-05-18T12:33:12Z"},{"alias_kind":"pith_short_16","alias_value":"7URMXWHTH533JITE","created_at":"2026-05-18T12:33:12Z"},{"alias_kind":"pith_short_8","alias_value":"7URMXWHT","created_at":"2026-05-18T12:33:12Z"}],"graph_snapshots":[{"event_id":"sha256:4321714c460d81d03923fd066073fac9afba004aeea3eb57128217b852027b0c","target":"graph","created_at":"2026-05-17T23:46:29Z","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 consider one-particle reducible (1PR) contributions to QED and scalar QED processes in external fields, at one-loop and two-loop order. We investigate three cases in detail: constant crossed fields, constant magnetic fields, and plane waves. We find that 1PR tadpole contributions in plane waves and constant crossed fields are non-zero, but contribute only divergences to be renormalised away. In constant magnetic fields, on the other hand, tadpole contributions give physical corrections to processes at one-loop and beyond. Our calculations are exact in the external fields and we give strong ","authors_text":"Anton Ilderton, James P. Edwards, Naser Ahmadiniaz","cross_cats":["hep-ph"],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"hep-th","submitted_at":"2019-01-27T18:25:56Z","title":"Reducible contributions to quantum electrodynamics in external fields"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1901.09416","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":"sha256:01d25915d19b19289321e3e57a98879146c08618a8a2af9c8c7eece0ad3e9142","target":"record","created_at":"2026-05-17T23:46:29Z","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":"5800678fb5dca6ca12b8abec0e40eca81a60b152a0bafa4b2c07317a02d6ff1d","cross_cats_sorted":["hep-ph"],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"hep-th","submitted_at":"2019-01-27T18:25:56Z","title_canon_sha256":"3d48754e3cc3cdc5076f7181dfcfb25d7c21006b06e23176a58105d1ccb5acb3"},"schema_version":"1.0","source":{"id":"1901.09416","kind":"arxiv","version":2}},"canonical_sha256":"fd22cbd8f33f77b4a264b9837266d45af64f680bb1de999cda2d6052a7e287b0","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"fd22cbd8f33f77b4a264b9837266d45af64f680bb1de999cda2d6052a7e287b0","first_computed_at":"2026-05-17T23:46:29.048163Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-17T23:46:29.048163Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"ik04UpPDxFzoIKfw+fcW77eWSTIomKzYAIhbLIA3yMoeqXvU7qqQjqn6tz8wKYs2wvuWsIeEWIeblLMX7m3dCg==","signature_status":"signed_v1","signed_at":"2026-05-17T23:46:29.048808Z","signed_message":"canonical_sha256_bytes"},"source_id":"1901.09416","source_kind":"arxiv","source_version":2}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:01d25915d19b19289321e3e57a98879146c08618a8a2af9c8c7eece0ad3e9142","sha256:4321714c460d81d03923fd066073fac9afba004aeea3eb57128217b852027b0c"],"state_sha256":"ed131ba09ea01e4e5b965070666c12425d5266026a9ee374e6889b88471993bc"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"OF8cW0S4FTzTz2WQTlhisPMhIwWyfBm531XRBXCdRQREtoM6BhRnfwl1LrrqPSqTM3VUhs2Rm/RU81WXajOICg==","signed_message":"bundle_sha256_bytes","signed_at":"2026-05-25T19:55:59.196977Z","bundle_sha256":"fd9a6d36e0818d37430c66f85c638c86e4d5248a96e4ef781e2dcb80fc634887"}}