{"paper":{"title":"OAM-Induced Lattice Rotation Reveals a Fractional Optimum in Fault-Tolerant GKP Quantum Sensing","license":"http://creativecommons.org/licenses/by/4.0/","headline":"A fractional OAM charge of 1.5 rotates the GKP lattice to an angle that reduces logical error probability by a factor of 23.9 while leaving quantum Fisher information unchanged.","cross_cats":[],"primary_cat":"quant-ph","authors_text":"Nandan S Bisht, Simanshu Kumar","submitted_at":"2026-05-13T09:49:16Z","abstract_excerpt":"Photon loss and dephasing rapidly degrade the sensitivity of quantum sensors, yet systematic methods for designing error-correcting codes whose geometry is simultaneously adapted to the sensing task and the noise channel do not exist. Here we establish that orbital-angular-momentum (OAM) encoding and Gottesman-Kitaev-Preskill (GKP) lattice geometry are structurally coupled: an OAM mode of topological charge $\\ell$ induces a phase-space rotation $\\theta_\\ell=\\ell\\pi/\\ell_{\\max}$, corresponding to a family of twisted GKP stabilizer lattices. Using an end-to-end differentiable Strawberry Fields--"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"The optimum occurs at the fractional charge ℓ=1.5 (θ=67.5°), implementable with a half-integer spiral phase plate, which reduces P_err by 23.9× relative to the square-lattice baseline while leaving F_Q unchanged to within 0.2%.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"That the Strawberry Fields–TensorFlow differentiable circuit faithfully models the combined photon-loss and dephasing channel and that the joint optimization over ℓ, r, and ε reaches the global optimum rather than a local one.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"Fractional OAM charge ℓ=1.5 induces an optimal 67.5° GKP lattice rotation that reduces error rate 23.9× with <0.2% loss in Fisher information and yields 41% higher metrological capacity.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"A fractional OAM charge of 1.5 rotates the GKP lattice to an angle that reduces logical error probability by a factor of 23.9 while leaving quantum Fisher information unchanged.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"48ce173220038c9d141c8671f4ea71c1f6e69d324b1215818e9a7787db2b5f89"},"source":{"id":"2605.13271","kind":"arxiv","version":2},"verdict":{"id":"b4362203-1a52-40f6-b20f-c885fa70e708","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-15T06:03:42.755861Z","strongest_claim":"The optimum occurs at the fractional charge ℓ=1.5 (θ=67.5°), implementable with a half-integer spiral phase plate, which reduces P_err by 23.9× relative to the square-lattice baseline while leaving F_Q unchanged to within 0.2%.","one_line_summary":"Fractional OAM charge ℓ=1.5 induces an optimal 67.5° GKP lattice rotation that reduces error rate 23.9× with <0.2% loss in Fisher information and yields 41% higher metrological capacity.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"That the Strawberry Fields–TensorFlow differentiable circuit faithfully models the combined photon-loss and dephasing channel and that the joint optimization over ℓ, r, and ε reaches the global optimum rather than a local one.","pith_extraction_headline":"A fractional OAM charge of 1.5 rotates the GKP lattice to an angle that reduces logical error probability by a factor of 23.9 while leaving quantum Fisher information unchanged."},"references":{"count":43,"sample":[{"doi":"","year":1976,"title":"C. W. Helstrom,Quantum Detection and Estima- tion Theory(Academic Press, New York, 1976). ISBN: 978-0-12-340050-5","work_id":"ae1c5525-0e94-4254-a6d3-4ce64753a458","ref_index":1,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"10.1038/nphoton.2011.35","year":2011,"title":"Advances in quantum metrology","work_id":"c2078ace-d1dd-4b4d-aeca-b0db15a5a4e4","ref_index":2,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"10.1038/ncomms2067","year":2012,"title":"R. Demkowicz-Dobrzański, J. Kołodyński, and M. Guţă, The elusive Heisenberg limit in quantum- enhanced metrology, Nat. Commun.3, 1063 (2012). doi:10.1038/ncomms2067","work_id":"83f4e381-1822-4906-9a9e-c772d82ebcb0","ref_index":3,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"10.1103/physrevlett.112.190403","year":2014,"title":"E. M. Kessleret al., Heisenberg-limited atom clocks based on entangled qubits, Phys. Rev. Lett.112, 190403 (2014). doi:10.1103/PhysRevLett.112.190403","work_id":"560fd0bd-0d9e-4e23-86d1-334255babbe5","ref_index":4,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"10.1103/physrevlett.112.080801","year":2014,"title":"Düret al., Improved quantum metrol- ogy using quantum error correction, Phys","work_id":"4a762b51-d2eb-4322-ae34-a1e6d2c21c82","ref_index":5,"cited_arxiv_id":"","is_internal_anchor":false}],"resolved_work":43,"snapshot_sha256":"e599c95d8d0145a7ab57932b5db199b980c51f22bd9763d035cda43c9b66edbd","internal_anchors":2},"formal_canon":{"evidence_count":2,"snapshot_sha256":"374f7bf864018a26cba43c11b46d0d7f5a1441290b55a08b39fc77b714214302"},"author_claims":{"count":0,"strong_count":0,"snapshot_sha256":"258153158e38e3291e3d48162225fcdb2d5a3ed65a07baac614ab91432fd4f57"},"builder_version":"pith-number-builder-2026-05-17-v1"}