Arbitrary controlled-phase gate on fluxonium qubits using differential ac Stark shifts

• DOI: 10.1103/physrevresearch.4.023040
• Publication Date: 2022-04-15T14:03:57Z
• Authors: Haonan Xiong; Quentin Ficheux; Aaron Somoroff; Long B. Nguyen; Ebru Dogan; Dario Rosenstock; Chen Wang; Konstantin N. Nes...; Maxim G. Vavilov; Vladimir E. Manuc...
• Keywords: Superconductivity (cond-mat.supr-con); Quantum Physics; Condensed Matter - Mesoscale and Nanoscale Physics; Physics; QC1-999; Condensed Matter - Superconductivity; Mesoscale and Nanoscale Physics (cond-mat.mes-hall); 0103 physical sciences; FOS: Physical sciences; Quantum Physics (quant-ph); 01 natural sciences

Large scale quantum computing motivates the invention of two-qubit gate schemes that not only maximize fidelity but also draw minimal resources. In case superconducting qubits, weak anharmonicity transmons imposes profound constraints on design, leading to increased complexity devices and control protocols. Here we demonstrate a resource-efficient over interaction strongly-anharmonic fluxonium qubits. Namely, applying an off-resonant drive noncomputational transitions in pair capacitively-coupled fluxoniums induces $\text{ZZ}$ due unequal ac Stark shifts computational levels. With continuous choice frequency amplitude, can either cancel static term or increase it by order magnitude enable controlled-phase (CP) with arbitrary programmed phase shift. The cross-entropy benchmarking these non-Clifford operations yields sub $1%$ error, limited solely incoherent processes. Our result demonstrates advantages circuits designing next generation processors.