High fidelity Two-qubit Gates on Fluxoniums Using a Tunable Coupler | NextBigFuture.com

Superconducting fluxonium qubits provide a promising alternative to transmons on the path toward large-scale superconductor-based quantum computing due to their better coherence and larger anharmonicity. A major challenge for multi-qubit fluxonium devices is the experimental demonstration of a scalable crosstalk-free multi-qubit architecture with high-fidelity single-qubit and two-qubit gates, single-shot readout, and state initialization. Researchers present a two-qubit fluxonium-based quantum processor with a tunable coupler element. They experimentally demonstrate fSim-type and controlled-Z-gates with 99.55 and 99.23% fidelities, respectively. The residual ZZ interaction is suppressed down to the few kHz levels. Using a galvanically coupled flux control line. Researchers implement high-fidelity single-qubit gates and ground state initialization with a single arbitrary waveform generator channel per qubit.