{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2026:K4ZPO7T4K3KCOX6AI5S3UIOYXB","short_pith_number":"pith:K4ZPO7T4","canonical_record":{"source":{"id":"2602.13975","kind":"arxiv","version":3},"metadata":{"license":"http://creativecommons.org/licenses/by-nc-nd/4.0/","primary_cat":"cond-mat.mes-hall","submitted_at":"2026-02-15T03:26:06Z","cross_cats_sorted":[],"title_canon_sha256":"5a6bf8673594438548c9ee69892f63f4182defcf58ad9a6acf088ade82611e9c","abstract_canon_sha256":"e435c4ad6fa893b7dc3904951ad5cca1fa941d48d9603fead46c42cf8c543f4b"},"schema_version":"1.0"},"canonical_sha256":"5732f77e7c56d4275fc04765ba21d8b86cc37eaad00c561bc86902f14b3a1f4b","source":{"kind":"arxiv","id":"2602.13975","version":3},"source_aliases":[{"alias_kind":"arxiv","alias_value":"2602.13975","created_at":"2026-06-19T16:12:18Z"},{"alias_kind":"arxiv_version","alias_value":"2602.13975v3","created_at":"2026-06-19T16:12:18Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2602.13975","created_at":"2026-06-19T16:12:18Z"},{"alias_kind":"pith_short_12","alias_value":"K4ZPO7T4K3KC","created_at":"2026-06-19T16:12:18Z"},{"alias_kind":"pith_short_16","alias_value":"K4ZPO7T4K3KCOX6A","created_at":"2026-06-19T16:12:18Z"},{"alias_kind":"pith_short_8","alias_value":"K4ZPO7T4","created_at":"2026-06-19T16:12:18Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2026:K4ZPO7T4K3KCOX6AI5S3UIOYXB","target":"record","payload":{"canonical_record":{"source":{"id":"2602.13975","kind":"arxiv","version":3},"metadata":{"license":"http://creativecommons.org/licenses/by-nc-nd/4.0/","primary_cat":"cond-mat.mes-hall","submitted_at":"2026-02-15T03:26:06Z","cross_cats_sorted":[],"title_canon_sha256":"5a6bf8673594438548c9ee69892f63f4182defcf58ad9a6acf088ade82611e9c","abstract_canon_sha256":"e435c4ad6fa893b7dc3904951ad5cca1fa941d48d9603fead46c42cf8c543f4b"},"schema_version":"1.0"},"canonical_sha256":"5732f77e7c56d4275fc04765ba21d8b86cc37eaad00c561bc86902f14b3a1f4b","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-06-19T16:12:18.665729Z","signature_b64":"rwy3sJAu746chMUoW/qZZ4OuwylitxaniWmTVc5P5t0XIGwDHSKTE6u5tSur5hs8VO6eKwK1sGcCa3dVmZ8BDw==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"5732f77e7c56d4275fc04765ba21d8b86cc37eaad00c561bc86902f14b3a1f4b","last_reissued_at":"2026-06-19T16:12:18.665301Z","signature_status":"signed_v1","first_computed_at":"2026-06-19T16:12:18.665301Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"2602.13975","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":"2026-06-19T16:12:18Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"ON7hz750vterA1tZusaef379yS3+Wg8kH79cVXlA0LYxan/dLSLbFvBMUH3uoTQzw/8zivUtTEcSqmznlzKFAw==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-06-27T17:20:47.282486Z"},"content_sha256":"a39d29c430aa8f236006c4fc9e04b7fd288d5cf0417d4ad6d9d39b89dcb8e3f0","schema_version":"1.0","event_id":"sha256:a39d29c430aa8f236006c4fc9e04b7fd288d5cf0417d4ad6d9d39b89dcb8e3f0"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2026:K4ZPO7T4K3KCOX6AI5S3UIOYXB","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"Ion Concentration and Voltage Imaging with Fluorescent Nanodiamonds","license":"http://creativecommons.org/licenses/by-nc-nd/4.0/","headline":"Fluorescent nanodiamonds enable optical imaging of voltage and ion concentrations via NV charge-state switching.","cross_cats":[],"primary_cat":"cond-mat.mes-hall","authors_text":"Anita Quigley, Hiroshi Abe, Nikolai Dontschuk, Patrick Voorhoeve, Philipp Reineck, Qiang Sun, Rob Kapsa, Takeshi Ohshima","submitted_at":"2026-02-15T03:26:06Z","abstract_excerpt":"The nitrogen-vacancy (NV) center in diamond exists in different charge states with distinct photoluminescence properties, which are sensitive to the nanoscale electrochemical environment. Hence, the NV charge state is emerging as a powerful all-optical platform for nanoscale sensing and imaging. Although significant progress has been made in engineering near-surface NV centers in bulk diamond, controlling the NV charge state in fluorescent nanodiamonds (FNDs) has proven challenging, limiting the sensitivity and reliability of FND-based charge state sensing. Here, we demonstrate reliable, rever"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"In aqueous electrochemical cells, we demonstrate voltage and ion concentration imaging based on the NV charge state in self-assembled FND layers on transparent substrates. Applied voltages reliably modulate the FND PL with a sensitivity of up to 16 mV Hz^{-1/2}. FND PL is also modulated by local changes in salt concentration with a sensitivity of up to 1.8% per millimolar NaCl.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"The observed photoluminescence modulation is caused by controlled switching between NV^0 and NV^+ charge states rather than other surface or environmental effects such as pH drift or temperature changes in the aqueous cell.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"Fluorescent nanodiamonds enable all-optical imaging of voltage (up to 16 mV Hz^{-1/2}) and ion concentration (1.8% per mM NaCl) via reversible NV charge state switching in aqueous cells.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"Fluorescent nanodiamonds enable optical imaging of voltage and ion concentrations via NV charge-state switching.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"921fcc1435445fef762536befb4f1b697fe2c9829fe5ac0f9447c74551502b87"},"source":{"id":"2602.13975","kind":"arxiv","version":3},"verdict":{"id":"8b580672-bc66-4405-9e9e-cb62c953e3cc","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-15T22:25:49.205958Z","strongest_claim":"In aqueous electrochemical cells, we demonstrate voltage and ion concentration imaging based on the NV charge state in self-assembled FND layers on transparent substrates. Applied voltages reliably modulate the FND PL with a sensitivity of up to 16 mV Hz^{-1/2}. FND PL is also modulated by local changes in salt concentration with a sensitivity of up to 1.8% per millimolar NaCl.","one_line_summary":"Fluorescent nanodiamonds enable all-optical imaging of voltage (up to 16 mV Hz^{-1/2}) and ion concentration (1.8% per mM NaCl) via reversible NV charge state switching in aqueous cells.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"The observed photoluminescence modulation is caused by controlled switching between NV^0 and NV^+ charge states rather than other surface or environmental effects such as pH drift or temperature changes in the aqueous cell.","pith_extraction_headline":"Fluorescent nanodiamonds enable optical imaging of voltage and ion concentrations via NV charge-state switching."},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2602.13975/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":"8b580672-bc66-4405-9e9e-cb62c953e3cc"},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-06-19T16:12:18Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"vZ/rbkEyjmJ2SlmtdEz3nFG6PqNkbYU/ULzL9qAUA4NAxZxsU/UpJIXpDs4+2JzM1Q5w2B85wmZpA+Neu2ITBA==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-06-27T17:20:47.282931Z"},"content_sha256":"f2a7600d35cd3a88240a8a6ce62a021a1ff629a721f7226aa789b4be9a086625","schema_version":"1.0","event_id":"sha256:f2a7600d35cd3a88240a8a6ce62a021a1ff629a721f7226aa789b4be9a086625"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/K4ZPO7T4K3KCOX6AI5S3UIOYXB/bundle.json","state_url":"https://pith.science/pith/K4ZPO7T4K3KCOX6AI5S3UIOYXB/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/K4ZPO7T4K3KCOX6AI5S3UIOYXB/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":"2026-06-27T17:20:47Z","links":{"resolver":"https://pith.science/pith/K4ZPO7T4K3KCOX6AI5S3UIOYXB","bundle":"https://pith.science/pith/K4ZPO7T4K3KCOX6AI5S3UIOYXB/bundle.json","state":"https://pith.science/pith/K4ZPO7T4K3KCOX6AI5S3UIOYXB/state.json","well_known_bundle":"https://pith.science/.well-known/pith/K4ZPO7T4K3KCOX6AI5S3UIOYXB/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2026:K4ZPO7T4K3KCOX6AI5S3UIOYXB","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":"e435c4ad6fa893b7dc3904951ad5cca1fa941d48d9603fead46c42cf8c543f4b","cross_cats_sorted":[],"license":"http://creativecommons.org/licenses/by-nc-nd/4.0/","primary_cat":"cond-mat.mes-hall","submitted_at":"2026-02-15T03:26:06Z","title_canon_sha256":"5a6bf8673594438548c9ee69892f63f4182defcf58ad9a6acf088ade82611e9c"},"schema_version":"1.0","source":{"id":"2602.13975","kind":"arxiv","version":3}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"2602.13975","created_at":"2026-06-19T16:12:18Z"},{"alias_kind":"arxiv_version","alias_value":"2602.13975v3","created_at":"2026-06-19T16:12:18Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.2602.13975","created_at":"2026-06-19T16:12:18Z"},{"alias_kind":"pith_short_12","alias_value":"K4ZPO7T4K3KC","created_at":"2026-06-19T16:12:18Z"},{"alias_kind":"pith_short_16","alias_value":"K4ZPO7T4K3KCOX6A","created_at":"2026-06-19T16:12:18Z"},{"alias_kind":"pith_short_8","alias_value":"K4ZPO7T4","created_at":"2026-06-19T16:12:18Z"}],"graph_snapshots":[{"event_id":"sha256:f2a7600d35cd3a88240a8a6ce62a021a1ff629a721f7226aa789b4be9a086625","target":"graph","created_at":"2026-06-19T16:12:18Z","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":4,"items":[{"attestation":"unclaimed","claim_id":"C1","kind":"strongest_claim","source":"verdict.strongest_claim","status":"machine_extracted","text":"In aqueous electrochemical cells, we demonstrate voltage and ion concentration imaging based on the NV charge state in self-assembled FND layers on transparent substrates. Applied voltages reliably modulate the FND PL with a sensitivity of up to 16 mV Hz^{-1/2}. FND PL is also modulated by local changes in salt concentration with a sensitivity of up to 1.8% per millimolar NaCl."},{"attestation":"unclaimed","claim_id":"C2","kind":"weakest_assumption","source":"verdict.weakest_assumption","status":"machine_extracted","text":"The observed photoluminescence modulation is caused by controlled switching between NV^0 and NV^+ charge states rather than other surface or environmental effects such as pH drift or temperature changes in the aqueous cell."},{"attestation":"unclaimed","claim_id":"C3","kind":"one_line_summary","source":"verdict.one_line_summary","status":"machine_extracted","text":"Fluorescent nanodiamonds enable all-optical imaging of voltage (up to 16 mV Hz^{-1/2}) and ion concentration (1.8% per mM NaCl) via reversible NV charge state switching in aqueous cells."},{"attestation":"unclaimed","claim_id":"C4","kind":"headline","source":"verdict.pith_extraction.headline","status":"machine_extracted","text":"Fluorescent nanodiamonds enable optical imaging of voltage and ion concentrations via NV charge-state switching."}],"snapshot_sha256":"921fcc1435445fef762536befb4f1b697fe2c9829fe5ac0f9447c74551502b87"},"formal_canon":{"evidence_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"integrity":{"available":true,"clean":true,"detectors_run":[],"endpoint":"/pith/2602.13975/integrity.json","findings":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938","summary":{"advisory":0,"by_detector":{},"critical":0,"informational":0}},"paper":{"abstract_excerpt":"The nitrogen-vacancy (NV) center in diamond exists in different charge states with distinct photoluminescence properties, which are sensitive to the nanoscale electrochemical environment. Hence, the NV charge state is emerging as a powerful all-optical platform for nanoscale sensing and imaging. Although significant progress has been made in engineering near-surface NV centers in bulk diamond, controlling the NV charge state in fluorescent nanodiamonds (FNDs) has proven challenging, limiting the sensitivity and reliability of FND-based charge state sensing. Here, we demonstrate reliable, rever","authors_text":"Anita Quigley, Hiroshi Abe, Nikolai Dontschuk, Patrick Voorhoeve, Philipp Reineck, Qiang Sun, Rob Kapsa, Takeshi Ohshima","cross_cats":[],"headline":"Fluorescent nanodiamonds enable optical imaging of voltage and ion concentrations via NV charge-state switching.","license":"http://creativecommons.org/licenses/by-nc-nd/4.0/","primary_cat":"cond-mat.mes-hall","submitted_at":"2026-02-15T03:26:06Z","title":"Ion Concentration and Voltage Imaging with Fluorescent Nanodiamonds"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2602.13975","kind":"arxiv","version":3},"verdict":{"created_at":"2026-05-15T22:25:49.205958Z","id":"8b580672-bc66-4405-9e9e-cb62c953e3cc","model_set":{"reader":"grok-4.3"},"one_line_summary":"Fluorescent nanodiamonds enable all-optical imaging of voltage (up to 16 mV Hz^{-1/2}) and ion concentration (1.8% per mM NaCl) via reversible NV charge state switching in aqueous cells.","pipeline_version":"pith-pipeline@v0.9.0","pith_extraction_headline":"Fluorescent nanodiamonds enable optical imaging of voltage and ion concentrations via NV charge-state switching.","strongest_claim":"In aqueous electrochemical cells, we demonstrate voltage and ion concentration imaging based on the NV charge state in self-assembled FND layers on transparent substrates. Applied voltages reliably modulate the FND PL with a sensitivity of up to 16 mV Hz^{-1/2}. FND PL is also modulated by local changes in salt concentration with a sensitivity of up to 1.8% per millimolar NaCl.","weakest_assumption":"The observed photoluminescence modulation is caused by controlled switching between NV^0 and NV^+ charge states rather than other surface or environmental effects such as pH drift or temperature changes in the aqueous cell."}},"verdict_id":"8b580672-bc66-4405-9e9e-cb62c953e3cc"}}],"author_attestations":[],"timestamp_anchors":[],"storage_attestations":[],"citation_signatures":[],"replication_records":[],"corrections":[],"mirror_hints":[],"record_created":{"event_id":"sha256:a39d29c430aa8f236006c4fc9e04b7fd288d5cf0417d4ad6d9d39b89dcb8e3f0","target":"record","created_at":"2026-06-19T16:12:18Z","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":"e435c4ad6fa893b7dc3904951ad5cca1fa941d48d9603fead46c42cf8c543f4b","cross_cats_sorted":[],"license":"http://creativecommons.org/licenses/by-nc-nd/4.0/","primary_cat":"cond-mat.mes-hall","submitted_at":"2026-02-15T03:26:06Z","title_canon_sha256":"5a6bf8673594438548c9ee69892f63f4182defcf58ad9a6acf088ade82611e9c"},"schema_version":"1.0","source":{"id":"2602.13975","kind":"arxiv","version":3}},"canonical_sha256":"5732f77e7c56d4275fc04765ba21d8b86cc37eaad00c561bc86902f14b3a1f4b","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"5732f77e7c56d4275fc04765ba21d8b86cc37eaad00c561bc86902f14b3a1f4b","first_computed_at":"2026-06-19T16:12:18.665301Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-06-19T16:12:18.665301Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"rwy3sJAu746chMUoW/qZZ4OuwylitxaniWmTVc5P5t0XIGwDHSKTE6u5tSur5hs8VO6eKwK1sGcCa3dVmZ8BDw==","signature_status":"signed_v1","signed_at":"2026-06-19T16:12:18.665729Z","signed_message":"canonical_sha256_bytes"},"source_id":"2602.13975","source_kind":"arxiv","source_version":3}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:a39d29c430aa8f236006c4fc9e04b7fd288d5cf0417d4ad6d9d39b89dcb8e3f0","sha256:f2a7600d35cd3a88240a8a6ce62a021a1ff629a721f7226aa789b4be9a086625"],"state_sha256":"d98997f517edc2e9df4328bd2d73a837973da2083c2e38377390c51bf433ea25"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"e8rSDgpDRvYsOl2V9+zhMZKRADRGw+xVJHVOnL1lJmhZZ3scUx7HUQDyvqQFyuLJUl3emQMQTpmuIqurLECvDg==","signed_message":"bundle_sha256_bytes","signed_at":"2026-06-27T17:20:47.285031Z","bundle_sha256":"f0f06c29d41e5d15fc4c97bf5a29ede5420f4427d280148ebe048c037b53fcde"}}