{"paper":{"title":"Variational quantum state preparation within an entangle-rotate circuit framework for quantum-enhanced metrology in noisy systems","license":"http://arxiv.org/licenses/nonexclusive-distrib/1.0/","headline":"Optimizing repeated entangle-rotate layers in a variational circuit maximizes quantum Fisher information for metrology even when noise is present.","cross_cats":[],"primary_cat":"quant-ph","authors_text":"Jeffrey Larson, Juan C. Zu\\~niga Castro, Matt Menickelly, Michael A. Perlin, Robert J. Lewis-Swan, Sri Hari Krishna Narayanan, Yicheng Zhang","submitted_at":"2026-04-16T16:40:43Z","abstract_excerpt":"We investigate the generation of quantum states for precision metrology in noisy two-level systems. These states are obtained by optimizing a variational quantum circuit to maximize the quantum Fisher information (QFI) of the output state for a given decoherence rate and interaction Hamiltonian. The circuit architecture, inspired by twist-and-turn schemes, features a sequence of $n$ entangling layers, each consisting of entangling gates followed by a global rotation. We observe notable improvements in the QFI as the circuit layer depth increases, even for appreciable noise rates, demonstrating"},"claims":{"count":4,"items":[{"kind":"strongest_claim","text":"We observe notable improvements in the QFI as the circuit layer depth increases, even for appreciable noise rates, demonstrating that our entangle-rotate architecture expands the accessible state space under realistic noise conditions.","source":"verdict.strongest_claim","status":"machine_extracted","claim_id":"C1","attestation":"unclaimed"},{"kind":"weakest_assumption","text":"The numerical optimization of variational parameters converges to states that are sufficiently close to the global maximum of QFI for the chosen noise model and Hamiltonian.","source":"verdict.weakest_assumption","status":"machine_extracted","claim_id":"C2","attestation":"unclaimed"},{"kind":"one_line_summary","text":"An entangle-rotate variational circuit improves QFI for quantum metrology in noisy systems, with gains persisting as circuit depth increases even at appreciable decoherence rates.","source":"verdict.one_line_summary","status":"machine_extracted","claim_id":"C3","attestation":"unclaimed"},{"kind":"headline","text":"Optimizing repeated entangle-rotate layers in a variational circuit maximizes quantum Fisher information for metrology even when noise is present.","source":"verdict.pith_extraction.headline","status":"machine_extracted","claim_id":"C4","attestation":"unclaimed"}],"snapshot_sha256":"7efbe6bfdca645ef194c404571d71f16b9c05a350f4c7f9b08d37ca42c84f540"},"source":{"id":"2604.15209","kind":"arxiv","version":1},"verdict":{"id":"254e679c-8701-4592-9f42-80611858aa63","model_set":{"reader":"grok-4.3"},"created_at":"2026-05-10T10:36:56.299209Z","strongest_claim":"We observe notable improvements in the QFI as the circuit layer depth increases, even for appreciable noise rates, demonstrating that our entangle-rotate architecture expands the accessible state space under realistic noise conditions.","one_line_summary":"An entangle-rotate variational circuit improves QFI for quantum metrology in noisy systems, with gains persisting as circuit depth increases even at appreciable decoherence rates.","pipeline_version":"pith-pipeline@v0.9.0","weakest_assumption":"The numerical optimization of variational parameters converges to states that are sufficiently close to the global maximum of QFI for the chosen noise model and Hamiltonian.","pith_extraction_headline":"Optimizing repeated entangle-rotate layers in a variational circuit maximizes quantum Fisher information for metrology even when noise is present."},"integrity":{"clean":true,"summary":{"advisory":0,"critical":0,"by_detector":{},"informational":0},"endpoint":"/pith/2604.15209/integrity.json","findings":[],"available":true,"detectors_run":[],"snapshot_sha256":"c28c3603d3b5d939e8dc4c7e95fa8dfce3d595e45f758748cecf8e644a296938"},"references":{"count":64,"sample":[{"doi":"","year":null,"title":"For example, we compute GHZ fidelities (F(n) GHZ) by setting|Ψ⟩=|GHZ,Φ⟩[see Eq","work_id":"86271ddc-32ed-480c-b45b-d0df7b22355d","ref_index":1,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":null,"title":"In the text we use the CES to delineate the uncorre- lated regime at the decoherenceγ 2 where Θ(1) I = 0","work_id":"3afc67fe-275c-4359-b50b-33ec978ea4f1","ref_index":2,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":null,"title":"In the text, we present the scaled squeezing parameter (N ξ2 s)−1 where larger values correspond to states exhibit- ing squeezed-like character","work_id":"6d75b37b-988a-43af-9ce0-d06d71904663","ref_index":3,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":null,"title":"Bounded from above by the QFI, the CFI quantifies the extent to which readout restricted to collective observables may exploit a given state’s metro- logical potential","work_id":"4ee44cf1-7e15-4ab9-9d86-93732bfd460b","ref_index":4,"cited_arxiv_id":"","is_internal_anchor":false},{"doi":"","year":null,"title":"2 as a function of the scaled decoherence strength γ/χ","work_id":"55d8db93-ccf8-43f2-8960-6a54bdfba0f5","ref_index":5,"cited_arxiv_id":"","is_internal_anchor":false}],"resolved_work":64,"snapshot_sha256":"fcbf63d3d38bff49b127fe21813e3520869cbf41da6227dbbd973f09c23573f6","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"}