{"ID":2882438,"CreatedAt":"2026-06-01T04:54:23.091178241Z","UpdatedAt":"2026-06-01T04:54:23.091178241Z","DeletedAt":null,"paper_url":"https://arxiv.org/abs/2508.10807","arxiv_id":"2508.10807","title":"Parity Cross-Resonance: A Multiqubit Gate","abstract":"We present a native three-qubit entangling gate that exploits engineered interactions to realize control-control-target and control-target-target operations in a single coherent step. Unlike conventional decompositions into multiple two-qubit gates, our hybrid optimization approach selectively amplifies desired interactions while suppressing unwanted couplings, yielding robust performance across the computational subspace and beyond. The new gate can be classified as a cross-resonance gate. We show it can be utilized in several ways, for example, in GHZ triplet state preparation, Toffoli-class logic demonstrations with many-body interactions, and in implementing a controlled-ZZ gate. The latter maps the parity of two data qubits directly onto a measurement qubit, enabling faster and higher-fidelity stabilizer measurements in surface-code quantum error correction. In all these examples, we show that the three-qubit gate performance remains robust across Hilbert space sizes, as confirmed by testing under increasing total excitation numbers. This work lays the foundation for co-designing circuit architectures and control protocols that leverage native multiqubit interactions as core elements of next-generation superconducting quantum processors.","short_abstract":"We present a native three-qubit entangling gate that exploits engineered interactions to realize control-control-target and control-target-target operations in a single coherent step. Unlike conventional decompositions into multiple two-qubit gates, our hybrid optimization approach selectively amplifies desired interac...","url_abs":"https://arxiv.org/abs/2508.10807","url_pdf":"https://arxiv.org/pdf/2508.10807v1","authors":"[\"Xuexin Xu\",\"Siyu Wang\",\"Radhika Joshi\",\"Rihan Hai\",\"Mohammad H. Ansari\"]","published":"2025-08-14T16:26:32Z","proceeding":"quant-ph","tasks":"[\"quant-ph\",\"cs.LG\",\"math.OC\"]","methods":"[]","has_code":false}