{"paper":{"title":"Observation of Subnatural-Linewidth Biphotons In a Two-Level Atomic Ensemble","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":["quant-ph"],"primary_cat":"physics.atom-ph","authors_text":"Chih-Sung Chuu, Chin-Te Wu, Ite A. Yu, Jyun-Kai Lin, Ravikumar Chinnarasu, Shengwang Du, Tzu-Hsiang Chien","submitted_at":"2025-01-21T06:00:05Z","abstract_excerpt":"Biphotons and single photons with narrow bandwidths and long coherence times are essential to the realization of long-distance quantum communication (LDQC) and linear optical quantum computing (LOQC). In this Letter, we manipulate the biphoton wave functions of the spontaneous four-wave mixing in a two-level atomic ensemble with a single-laser pump scheme. Our innovative experimental approach enables the generation of biphotons with a sub-MHz bandwidth of 0.36 MHz, a record spectral brightness of $2.28\\times10^7$${\\rm s}^{-1}{\\rm mW}^{-1}{\\rm MHz}^{-1}$, and a temporally symmetric wave packet "},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2501.11908","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":""},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2501.11908/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"}