{"record_type":"pith_number_record","schema_url":"https://pith.science/schemas/pith-number/v1.json","pith_number":"pith:2023:XEU7GSGCJ5YGXP3NT36KYESGID","short_pith_number":"pith:XEU7GSGC","schema_version":"1.0","canonical_sha256":"b929f348c24f706bbf6d9efcac124640e0956d1c8b0885752ee85f31ecce9c9d","source":{"kind":"arxiv","id":"2303.04798","version":2},"attestation_state":"computed","paper":{"title":"Hierarchical memories: Simulating quantum LDPC codes with local gates","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":[],"primary_cat":"quant-ph","authors_text":"Anirudh Krishna, Christopher A. Pattison, John Preskill","submitted_at":"2023-03-08T18:48:12Z","abstract_excerpt":"Constant-rate low-density parity-check (LDPC) codes are promising candidates for constructing efficient fault-tolerant quantum memories. However, if physical gates are subject to geometric-locality constraints, it becomes challenging to realize these codes. In this paper, we construct a new family of $[[N,K,D]]$ codes, referred to as hierarchical codes, that encode a number of logical qubits $K = \\Omega(N/\\log(N)^2)$. The N-th element of this code family is obtained by concatenating a constant-rate quantum LDPC code with a surface code; nearest-neighbor gates in two dimensions are sufficient t"},"verification_status":{"content_addressed":true,"pith_receipt":true,"author_attested":false,"weak_author_claims":0,"strong_author_claims":0,"externally_anchored":false,"storage_verified":false,"citation_signatures":0,"replication_records":0,"graph_snapshot":true,"references_resolved":false,"formal_links_present":false},"canonical_record":{"source":{"id":"2303.04798","kind":"arxiv","version":2},"metadata":{"license":"http://creativecommons.org/licenses/by/4.0/","primary_cat":"quant-ph","submitted_at":"2023-03-08T18:48:12Z","cross_cats_sorted":[],"title_canon_sha256":"f66868305a88f1375ceab77f696e185ae6d8eef9cacf615632021db6278fa064","abstract_canon_sha256":"b2e56d6e219969f4e9c354e5627f08b4a7988e05dce48120bb0a68cbd37ad982"},"schema_version":"1.0"},"receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-07-05T10:58:57.693895Z","signature_b64":"+dq2B9Tfb9sJ16DmTLgd3OuTx48LfSjbNQT4n1m3aHgTtljnj6lnSZBDcqHGSQohUO5G50MKH5d9mSK7KjZSBQ==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"b929f348c24f706bbf6d9efcac124640e0956d1c8b0885752ee85f31ecce9c9d","last_reissued_at":"2026-07-05T10:58:57.693398Z","signature_status":"signed_v1","first_computed_at":"2026-07-05T10:58:57.693398Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"graph_snapshot":{"paper":{"title":"Hierarchical memories: Simulating quantum LDPC codes with local gates","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":[],"primary_cat":"quant-ph","authors_text":"Anirudh Krishna, Christopher A. Pattison, John Preskill","submitted_at":"2023-03-08T18:48:12Z","abstract_excerpt":"Constant-rate low-density parity-check (LDPC) codes are promising candidates for constructing efficient fault-tolerant quantum memories. However, if physical gates are subject to geometric-locality constraints, it becomes challenging to realize these codes. In this paper, we construct a new family of $[[N,K,D]]$ codes, referred to as hierarchical codes, that encode a number of logical qubits $K = \\Omega(N/\\log(N)^2)$. The N-th element of this code family is obtained by concatenating a constant-rate quantum LDPC code with a surface code; nearest-neighbor gates in two dimensions are sufficient t"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2303.04798","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":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2303.04798/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"},"aliases":[{"alias_kind":"arxiv","alias_value":"2303.04798","created_at":"2026-07-05T10:58:57.693460+00:00"},{"alias_kind":"arxiv_version","alias_value":"2303.04798v2","created_at":"2026-07-05T10:58:57.693460+00:00"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2303.04798","created_at":"2026-07-05T10:58:57.693460+00:00"},{"alias_kind":"pith_short_12","alias_value":"XEU7GSGCJ5YG","created_at":"2026-07-05T10:58:57.693460+00:00"},{"alias_kind":"pith_short_16","alias_value":"XEU7GSGCJ5YGXP3N","created_at":"2026-07-05T10:58:57.693460+00:00"},{"alias_kind":"pith_short_8","alias_value":"XEU7GSGC","created_at":"2026-07-05T10:58:57.693460+00:00"}],"events":[],"event_summary":{},"paper_claims":[],"inbound_citations":{"count":1,"internal_anchor_count":0,"sample":[{"citing_arxiv_id":"2407.16176","citing_title":"Quantum memory based on concatenating surface codes and quantum Hamming codes","ref_index":41,"is_internal_anchor":false}]},"formal_canon":{"evidence_count":0,"sample":[],"anchors":[]},"links":{"html":"https://pith.science/pith/XEU7GSGCJ5YGXP3NT36KYESGID","json":"https://pith.science/pith/XEU7GSGCJ5YGXP3NT36KYESGID.json","graph_json":"https://pith.science/api/pith-number/XEU7GSGCJ5YGXP3NT36KYESGID/graph.json","events_json":"https://pith.science/api/pith-number/XEU7GSGCJ5YGXP3NT36KYESGID/events.json","paper":"https://pith.science/paper/XEU7GSGC"},"agent_actions":{"view_html":"https://pith.science/pith/XEU7GSGCJ5YGXP3NT36KYESGID","download_json":"https://pith.science/pith/XEU7GSGCJ5YGXP3NT36KYESGID.json","view_paper":"https://pith.science/paper/XEU7GSGC","resolve_alias":"https://pith.science/api/pith-number/resolve?arxiv=2303.04798&json=true","fetch_graph":"https://pith.science/api/pith-number/XEU7GSGCJ5YGXP3NT36KYESGID/graph.json","fetch_events":"https://pith.science/api/pith-number/XEU7GSGCJ5YGXP3NT36KYESGID/events.json","actions":{"anchor_timestamp":"https://pith.science/pith/XEU7GSGCJ5YGXP3NT36KYESGID/action/timestamp_anchor","attest_storage":"https://pith.science/pith/XEU7GSGCJ5YGXP3NT36KYESGID/action/storage_attestation","attest_author":"https://pith.science/pith/XEU7GSGCJ5YGXP3NT36KYESGID/action/author_attestation","sign_citation":"https://pith.science/pith/XEU7GSGCJ5YGXP3NT36KYESGID/action/citation_signature","submit_replication":"https://pith.science/pith/XEU7GSGCJ5YGXP3NT36KYESGID/action/replication_record"}},"created_at":"2026-07-05T10:58:57.693460+00:00","updated_at":"2026-07-05T10:58:57.693460+00:00"}