{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2022:NGPOYG6VDAFOEE4CYXYLULDVG7","short_pith_number":"pith:NGPOYG6V","canonical_record":{"source":{"id":"2204.08494","kind":"arxiv","version":3},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"quant-ph","submitted_at":"2022-04-18T18:01:58Z","cross_cats_sorted":[],"title_canon_sha256":"6ccd91a27dd8714c9142dc41ef780acbc950456586dbd7516feaec5aa4924188","abstract_canon_sha256":"9dcabe177c2fd64fc3e63d401cdc413cd2f61ff8153b8ba4a7cc56b5f717a790"},"schema_version":"1.0"},"canonical_sha256":"699eec1bd5180ae21382c5f0ba2c7537e64595a0eb2750e23fa334e5811f3ab8","source":{"kind":"arxiv","id":"2204.08494","version":3},"source_aliases":[{"alias_kind":"arxiv","alias_value":"2204.08494","created_at":"2026-07-05T05:21:24Z"},{"alias_kind":"arxiv_version","alias_value":"2204.08494v3","created_at":"2026-07-05T05:21:24Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2204.08494","created_at":"2026-07-05T05:21:24Z"},{"alias_kind":"pith_short_12","alias_value":"NGPOYG6VDAFO","created_at":"2026-07-05T05:21:24Z"},{"alias_kind":"pith_short_16","alias_value":"NGPOYG6VDAFOEE4C","created_at":"2026-07-05T05:21:24Z"},{"alias_kind":"pith_short_8","alias_value":"NGPOYG6V","created_at":"2026-07-05T05:21:24Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2022:NGPOYG6VDAFOEE4CYXYLULDVG7","target":"record","payload":{"canonical_record":{"source":{"id":"2204.08494","kind":"arxiv","version":3},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"quant-ph","submitted_at":"2022-04-18T18:01:58Z","cross_cats_sorted":[],"title_canon_sha256":"6ccd91a27dd8714c9142dc41ef780acbc950456586dbd7516feaec5aa4924188","abstract_canon_sha256":"9dcabe177c2fd64fc3e63d401cdc413cd2f61ff8153b8ba4a7cc56b5f717a790"},"schema_version":"1.0"},"canonical_sha256":"699eec1bd5180ae21382c5f0ba2c7537e64595a0eb2750e23fa334e5811f3ab8","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-07-05T05:21:24.943046Z","signature_b64":"4kjZ3TkpVSQFeQdHAM73/vrM0QwVW4wI+Q/zEcL76HGUOfPCc9+1QVa8Kzyz8XHVgPzxe8SWtJQ7xdJm9+g0AA==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"699eec1bd5180ae21382c5f0ba2c7537e64595a0eb2750e23fa334e5811f3ab8","last_reissued_at":"2026-07-05T05:21:24.942537Z","signature_status":"signed_v1","first_computed_at":"2026-07-05T05:21:24.942537Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"2204.08494","source_version":3,"attestation_state":"computed"},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-07-05T05:21:24Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"CM+pcWSizgPFydERDLUh1UFbHuTwNMV+jGsG+4AI5gj/BemlPt05nY5d5jM2A9JETiiy4oDgZUPyoxyZq1NaAw==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-08-04T12:37:13.040897Z"},"content_sha256":"c9b52bbb60d5767a30dfc58a40fd629119ad051d4ebc4f91d7d362f4a2269094","schema_version":"1.0","event_id":"sha256:c9b52bbb60d5767a30dfc58a40fd629119ad051d4ebc4f91d7d362f4a2269094"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2022:NGPOYG6VDAFOEE4CYXYLULDVG7","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"Training variational quantum circuits with CoVaR: covariance root finding with classical shadows","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"quant-ph","authors_text":"B\\'alint Koczor, Gregory Boyd","submitted_at":"2022-04-18T18:01:58Z","abstract_excerpt":"Exploiting near-term quantum computers and achieving practical value is a considerable and exciting challenge. Most prominent candidates as variational algorithms typically aim to find the ground state of a Hamiltonian by minimising a single classical (energy) surface which is sampled from by a quantum computer. Here we introduce a method we call CoVaR, an alternative means to exploit the power of variational circuits: We find eigenstates by finding joint roots of a polynomially growing number of properties of the quantum state as covariance functions between the Hamiltonian and an operator po"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2204.08494","kind":"arxiv","version":3},"verdict":{"id":null,"model_set":{},"created_at":null,"strongest_claim":"","one_line_summary":"","pipeline_version":null,"weakest_assumption":"","pith_extraction_headline":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2204.08494/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"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":"2026-07-05T05:21:24Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"yp58zUbbu/eAiuC7244w/EOcyxy91zmYeeMS3JnRKZnfxz6l5EZeSgjfshBX1umdELeDTWLZp6codhAMGx8KCA==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-08-04T12:37:13.041389Z"},"content_sha256":"abe4d3ddf64c14ff1dc4f032d3ef6892cd4aef7a85caec8712f0ed2ed2c1fff6","schema_version":"1.0","event_id":"sha256:abe4d3ddf64c14ff1dc4f032d3ef6892cd4aef7a85caec8712f0ed2ed2c1fff6"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/NGPOYG6VDAFOEE4CYXYLULDVG7/bundle.json","state_url":"https://pith.science/pith/NGPOYG6VDAFOEE4CYXYLULDVG7/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/NGPOYG6VDAFOEE4CYXYLULDVG7/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":"2026-08-04T12:37:13Z","links":{"resolver":"https://pith.science/pith/NGPOYG6VDAFOEE4CYXYLULDVG7","bundle":"https://pith.science/pith/NGPOYG6VDAFOEE4CYXYLULDVG7/bundle.json","state":"https://pith.science/pith/NGPOYG6VDAFOEE4CYXYLULDVG7/state.json","well_known_bundle":"https://pith.science/.well-known/pith/NGPOYG6VDAFOEE4CYXYLULDVG7/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2022:NGPOYG6VDAFOEE4CYXYLULDVG7","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":"9dcabe177c2fd64fc3e63d401cdc413cd2f61ff8153b8ba4a7cc56b5f717a790","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"quant-ph","submitted_at":"2022-04-18T18:01:58Z","title_canon_sha256":"6ccd91a27dd8714c9142dc41ef780acbc950456586dbd7516feaec5aa4924188"},"schema_version":"1.0","source":{"id":"2204.08494","kind":"arxiv","version":3}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"2204.08494","created_at":"2026-07-05T05:21:24Z"},{"alias_kind":"arxiv_version","alias_value":"2204.08494v3","created_at":"2026-07-05T05:21:24Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2204.08494","created_at":"2026-07-05T05:21:24Z"},{"alias_kind":"pith_short_12","alias_value":"NGPOYG6VDAFO","created_at":"2026-07-05T05:21:24Z"},{"alias_kind":"pith_short_16","alias_value":"NGPOYG6VDAFOEE4C","created_at":"2026-07-05T05:21:24Z"},{"alias_kind":"pith_short_8","alias_value":"NGPOYG6V","created_at":"2026-07-05T05:21:24Z"}],"graph_snapshots":[{"event_id":"sha256:abe4d3ddf64c14ff1dc4f032d3ef6892cd4aef7a85caec8712f0ed2ed2c1fff6","target":"graph","created_at":"2026-07-05T05:21:24Z","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"},"integrity":{"available":true,"clean":true,"detectors_run":[],"endpoint":"/pith/2204.08494/integrity.json","findings":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938","summary":{"advisory":0,"by_detector":{},"critical":0,"informational":0}},"paper":{"abstract_excerpt":"Exploiting near-term quantum computers and achieving practical value is a considerable and exciting challenge. Most prominent candidates as variational algorithms typically aim to find the ground state of a Hamiltonian by minimising a single classical (energy) surface which is sampled from by a quantum computer. Here we introduce a method we call CoVaR, an alternative means to exploit the power of variational circuits: We find eigenstates by finding joint roots of a polynomially growing number of properties of the quantum state as covariance functions between the Hamiltonian and an operator po","authors_text":"B\\'alint Koczor, Gregory Boyd","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"quant-ph","submitted_at":"2022-04-18T18:01:58Z","title":"Training variational quantum circuits with CoVaR: covariance root finding with classical shadows"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2204.08494","kind":"arxiv","version":3},"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:c9b52bbb60d5767a30dfc58a40fd629119ad051d4ebc4f91d7d362f4a2269094","target":"record","created_at":"2026-07-05T05:21:24Z","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":"9dcabe177c2fd64fc3e63d401cdc413cd2f61ff8153b8ba4a7cc56b5f717a790","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"quant-ph","submitted_at":"2022-04-18T18:01:58Z","title_canon_sha256":"6ccd91a27dd8714c9142dc41ef780acbc950456586dbd7516feaec5aa4924188"},"schema_version":"1.0","source":{"id":"2204.08494","kind":"arxiv","version":3}},"canonical_sha256":"699eec1bd5180ae21382c5f0ba2c7537e64595a0eb2750e23fa334e5811f3ab8","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"699eec1bd5180ae21382c5f0ba2c7537e64595a0eb2750e23fa334e5811f3ab8","first_computed_at":"2026-07-05T05:21:24.942537Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-07-05T05:21:24.942537Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"4kjZ3TkpVSQFeQdHAM73/vrM0QwVW4wI+Q/zEcL76HGUOfPCc9+1QVa8Kzyz8XHVgPzxe8SWtJQ7xdJm9+g0AA==","signature_status":"signed_v1","signed_at":"2026-07-05T05:21:24.943046Z","signed_message":"canonical_sha256_bytes"},"source_id":"2204.08494","source_kind":"arxiv","source_version":3}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:c9b52bbb60d5767a30dfc58a40fd629119ad051d4ebc4f91d7d362f4a2269094","sha256:abe4d3ddf64c14ff1dc4f032d3ef6892cd4aef7a85caec8712f0ed2ed2c1fff6"],"state_sha256":"3ac92a9a54970897e76eec9cce186592cb043a64f0e37b636dd559740a138803"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"SemValSIC47xC14x4T2/ezRBg026j21VKrbklCl62Ob2X5d+Y6God6qJER14AgN67WL8zkIRcS125M63A0tqBA==","signed_message":"bundle_sha256_bytes","signed_at":"2026-08-04T12:37:13.044858Z","bundle_sha256":"62f0c58e644da02d13e416735469eaf898d5d6e16f7af35605eef7a5fdac99c5"}}