{"paper":{"title":"Finding the ultra-narrow $^3\\!P_2 \\rightarrow \\, ^3\\!P_0$ electric quadrupole transition in Ni$^{12+}$ ion for an optical clock","license":"http://creativecommons.org/licenses/by/4.0/","headline":"","cross_cats":[],"primary_cat":"physics.atom-ph","authors_text":"Alexander Wilzewski, Charles Cheung, Dmytro Filin, Jos\\'e R. Crespo L\\'opez-Urrutia, Lukas J. Spie{\\ss}, Malte Wehrheim, Marianna S. Safronova, Piet O. Schmidt, Sergey G. Porsev, Shuying Chen","submitted_at":"2025-02-08T00:03:07Z","abstract_excerpt":"The Ni$^{12+}$ ion features an electronic transition with a natural width of only 8 mHz, allowing for a highly stable optical clock. We predict that the energy of this strongly forbidden $3s^2 3p^4\\, ^3\\!P_2 \\rightarrow 3s^2 3p^4 \\, ^3\\!P_0$ electric quadrupole transition is 20081(10) cm$^{-1}$. For this, we use both a hybrid approach combining configuration interaction (CI) with coupled-cluster (CC) method and a pure CI calculation for the complete 16-electron system, ensuring convergence. The resulting very small theoretical uncertainty of only 0.05\\% allowed us to find the transition experi"},"claims":{"count":0,"items":[],"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"source":{"id":"2502.05386","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/2502.05386/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"}