{"bundle_type":"pith_open_graph_bundle","bundle_version":"1.0","pith_number":"pith:2015:SAARX5NCH2YSQUXOUREZQLLWAI","short_pith_number":"pith:SAARX5NC","canonical_record":{"source":{"id":"1504.03603","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"quant-ph","submitted_at":"2015-04-14T16:10:29Z","cross_cats_sorted":[],"title_canon_sha256":"5fe0c0ab48d8e9346254ec658ada0b2acc8ff797c39cbaf8e5123ab49bf409a0","abstract_canon_sha256":"a4b5f057d70a736f24c8b745b5efe698c99bb0932059e4d55001f086ac89b85b"},"schema_version":"1.0"},"canonical_sha256":"90011bf5a23eb12852eea449982d76021832f53c54882573747e64d99bd3e154","source":{"kind":"arxiv","id":"1504.03603","version":1},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1504.03603","created_at":"2026-05-18T01:35:59Z"},{"alias_kind":"arxiv_version","alias_value":"1504.03603v1","created_at":"2026-05-18T01:35:59Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1504.03603","created_at":"2026-05-18T01:35:59Z"},{"alias_kind":"pith_short_12","alias_value":"SAARX5NCH2YS","created_at":"2026-05-18T12:29:39Z"},{"alias_kind":"pith_short_16","alias_value":"SAARX5NCH2YSQUXO","created_at":"2026-05-18T12:29:39Z"},{"alias_kind":"pith_short_8","alias_value":"SAARX5NC","created_at":"2026-05-18T12:29:39Z"}],"events":[{"event_type":"record_created","subject_pith_number":"pith:2015:SAARX5NCH2YSQUXOUREZQLLWAI","target":"record","payload":{"canonical_record":{"source":{"id":"1504.03603","kind":"arxiv","version":1},"metadata":{"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"quant-ph","submitted_at":"2015-04-14T16:10:29Z","cross_cats_sorted":[],"title_canon_sha256":"5fe0c0ab48d8e9346254ec658ada0b2acc8ff797c39cbaf8e5123ab49bf409a0","abstract_canon_sha256":"a4b5f057d70a736f24c8b745b5efe698c99bb0932059e4d55001f086ac89b85b"},"schema_version":"1.0"},"canonical_sha256":"90011bf5a23eb12852eea449982d76021832f53c54882573747e64d99bd3e154","receipt":{"kind":"pith_receipt","key_id":"pith-v1-2026-05","algorithm":"ed25519","signed_at":"2026-05-18T01:35:59.740851Z","signature_b64":"70/7ZljPD51GeSmcSBHYGEq/cxUB/W7hjuLxiQDs5Jo975DYe/ysLDdL/4niKX9zySkh54NJb/yczGrKtbSyCw==","signed_message":"canonical_sha256_bytes","builder_version":"pith-number-builder-2026-05-17-v1","receipt_version":"0.3","canonical_sha256":"90011bf5a23eb12852eea449982d76021832f53c54882573747e64d99bd3e154","last_reissued_at":"2026-05-18T01:35:59.740358Z","signature_status":"signed_v1","first_computed_at":"2026-05-18T01:35:59.740358Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"source_kind":"arxiv","source_id":"1504.03603","source_version":1,"attestation_state":"computed"},"signer":{"signer_id":"pith.science","signer_type":"pith_registry","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54"},"created_at":"2026-05-18T01:35:59Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"D+wRWVY6othXwqvocpR6Csw1UAv50gBppcjA1h40YxGVTQalU7s7J4wcPirEQLjZiFDoVfqPUAakY0UL4t9mCg==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-25T16:09:28.951155Z"},"content_sha256":"803fe60fb836abccb39bf4cf2f3c63b82c2d52eaad0ba222a62294bbaebbc6e4","schema_version":"1.0","event_id":"sha256:803fe60fb836abccb39bf4cf2f3c63b82c2d52eaad0ba222a62294bbaebbc6e4"},{"event_type":"graph_snapshot","subject_pith_number":"pith:2015:SAARX5NCH2YSQUXOUREZQLLWAI","target":"graph","payload":{"graph_snapshot":{"paper":{"title":"A small quantum absorption refrigerator with reversed couplings","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"","cross_cats":[],"primary_cat":"quant-ph","authors_text":"Nicolas Brunner, Paul Skrzypczyk, Ralph Silva","submitted_at":"2015-04-14T16:10:29Z","abstract_excerpt":"Small quantum absorption refrigerators have recently attracted renewed attention. Here we present a missing design of a two-qubit fridge, the main feature of which is that one of the two machine qubits is itself maintained at a temperature colder than the cold bath. This is achieved by 'reversing' the couplings to the baths compared to previous designs, where only a transition is maintained cold. We characterize the working regime and the efficiency of the fridge. We demonstrate the soundness of the model by deriving and solving a master equation. Finally, we discuss the performance of the fri"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1504.03603","kind":"arxiv","version":1},"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":"2026-05-18T01:35:59Z","supersedes":[],"prev_event":null,"signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"fZqXkiL4gOfJFQhIjjJg6Dv/wfey6MGs9RiYKoepwAGYhzwcfIfMsEwvbKwb4YpV5vfBydGL7+qYhrG2iHt6Dw==","signed_message":"open_graph_event_sha256_bytes","signed_at":"2026-05-25T16:09:28.951839Z"},"content_sha256":"017c89bc2e8474404e3b32cfa2341dc80c2d6dc36f53cbe5167a3619087476a4","schema_version":"1.0","event_id":"sha256:017c89bc2e8474404e3b32cfa2341dc80c2d6dc36f53cbe5167a3619087476a4"}],"timestamp_proofs":[],"mirror_hints":[{"mirror_type":"https","name":"Pith Resolver","base_url":"https://pith.science","bundle_url":"https://pith.science/pith/SAARX5NCH2YSQUXOUREZQLLWAI/bundle.json","state_url":"https://pith.science/pith/SAARX5NCH2YSQUXOUREZQLLWAI/state.json","well_known_bundle_url":"https://pith.science/.well-known/pith/SAARX5NCH2YSQUXOUREZQLLWAI/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":"2026-05-25T16:09:28Z","links":{"resolver":"https://pith.science/pith/SAARX5NCH2YSQUXOUREZQLLWAI","bundle":"https://pith.science/pith/SAARX5NCH2YSQUXOUREZQLLWAI/bundle.json","state":"https://pith.science/pith/SAARX5NCH2YSQUXOUREZQLLWAI/state.json","well_known_bundle":"https://pith.science/.well-known/pith/SAARX5NCH2YSQUXOUREZQLLWAI/bundle.json"},"state":{"state_type":"pith_open_graph_state","state_version":"1.0","pith_number":"pith:2015:SAARX5NCH2YSQUXOUREZQLLWAI","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":"a4b5f057d70a736f24c8b745b5efe698c99bb0932059e4d55001f086ac89b85b","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"quant-ph","submitted_at":"2015-04-14T16:10:29Z","title_canon_sha256":"5fe0c0ab48d8e9346254ec658ada0b2acc8ff797c39cbaf8e5123ab49bf409a0"},"schema_version":"1.0","source":{"id":"1504.03603","kind":"arxiv","version":1}},"source_aliases":[{"alias_kind":"arxiv","alias_value":"1504.03603","created_at":"2026-05-18T01:35:59Z"},{"alias_kind":"arxiv_version","alias_value":"1504.03603v1","created_at":"2026-05-18T01:35:59Z"},{"alias_kind":"doi","alias_value":"10.48550/arxiv.1504.03603","created_at":"2026-05-18T01:35:59Z"},{"alias_kind":"pith_short_12","alias_value":"SAARX5NCH2YS","created_at":"2026-05-18T12:29:39Z"},{"alias_kind":"pith_short_16","alias_value":"SAARX5NCH2YSQUXO","created_at":"2026-05-18T12:29:39Z"},{"alias_kind":"pith_short_8","alias_value":"SAARX5NC","created_at":"2026-05-18T12:29:39Z"}],"graph_snapshots":[{"event_id":"sha256:017c89bc2e8474404e3b32cfa2341dc80c2d6dc36f53cbe5167a3619087476a4","target":"graph","created_at":"2026-05-18T01:35:59Z","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":"Small quantum absorption refrigerators have recently attracted renewed attention. Here we present a missing design of a two-qubit fridge, the main feature of which is that one of the two machine qubits is itself maintained at a temperature colder than the cold bath. This is achieved by 'reversing' the couplings to the baths compared to previous designs, where only a transition is maintained cold. We characterize the working regime and the efficiency of the fridge. We demonstrate the soundness of the model by deriving and solving a master equation. Finally, we discuss the performance of the fri","authors_text":"Nicolas Brunner, Paul Skrzypczyk, Ralph Silva","cross_cats":[],"headline":"","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"quant-ph","submitted_at":"2015-04-14T16:10:29Z","title":"A small quantum absorption refrigerator with reversed couplings"},"references":{"count":0,"internal_anchors":0,"resolved_work":0,"sample":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"1504.03603","kind":"arxiv","version":1},"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":"sha256:803fe60fb836abccb39bf4cf2f3c63b82c2d52eaad0ba222a62294bbaebbc6e4","target":"record","created_at":"2026-05-18T01:35:59Z","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":"a4b5f057d70a736f24c8b745b5efe698c99bb0932059e4d55001f086ac89b85b","cross_cats_sorted":[],"license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","primary_cat":"quant-ph","submitted_at":"2015-04-14T16:10:29Z","title_canon_sha256":"5fe0c0ab48d8e9346254ec658ada0b2acc8ff797c39cbaf8e5123ab49bf409a0"},"schema_version":"1.0","source":{"id":"1504.03603","kind":"arxiv","version":1}},"canonical_sha256":"90011bf5a23eb12852eea449982d76021832f53c54882573747e64d99bd3e154","receipt":{"algorithm":"ed25519","builder_version":"pith-number-builder-2026-05-17-v1","canonical_sha256":"90011bf5a23eb12852eea449982d76021832f53c54882573747e64d99bd3e154","first_computed_at":"2026-05-18T01:35:59.740358Z","key_id":"pith-v1-2026-05","kind":"pith_receipt","last_reissued_at":"2026-05-18T01:35:59.740358Z","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","receipt_version":"0.3","signature_b64":"70/7ZljPD51GeSmcSBHYGEq/cxUB/W7hjuLxiQDs5Jo975DYe/ysLDdL/4niKX9zySkh54NJb/yczGrKtbSyCw==","signature_status":"signed_v1","signed_at":"2026-05-18T01:35:59.740851Z","signed_message":"canonical_sha256_bytes"},"source_id":"1504.03603","source_kind":"arxiv","source_version":1}}},"equivocations":[],"invalid_events":[],"applied_event_ids":["sha256:803fe60fb836abccb39bf4cf2f3c63b82c2d52eaad0ba222a62294bbaebbc6e4","sha256:017c89bc2e8474404e3b32cfa2341dc80c2d6dc36f53cbe5167a3619087476a4"],"state_sha256":"3ef721cae3075ec85bb856c3b350b029748aec69fa873efa3aa6eb551e1a0848"},"bundle_signature":{"signature_status":"signed_v1","algorithm":"ed25519","key_id":"pith-v1-2026-05","public_key_fingerprint":"8d4b5ee74e4693bcd1df2446408b0d54","signature_b64":"56Fx0rDXo8VEk2N9ceeOI1v5zsAUr7Bj/XaS5bAcjz9t0eni9sPL5mvt1e7dtWBTTqsexkq6txlrEHQyTPeLCg==","signed_message":"bundle_sha256_bytes","signed_at":"2026-05-25T16:09:28.958177Z","bundle_sha256":"af0637f3a517d064d78b20dc189e73ddc5cd62a3973bae7037af498998f692de"}}