Eliminating residual $ZZ$ interactions in a two-qubit system is essential for reducing coherent errors during quantum operations. In a superconducting circuit platform, coupling two transmon qubits via a transmon coupler has been shown to effectively suppress residual $ZZ$ interactions. However, in such systems, perfect cancellation usually requires the qubit-qubit detuning to be smaller than the individual qubit anharmonicities, which exacerbates frequency crowding and microwave crosstalk. To address this limitation, we introduce transmon-fluxonium-transmon (TFT) architecture, wherein two transmon qubits are coupled via a fluxonium qubit. The coupling mediated by the fluxonium eliminates residual $ZZ$ interactions even for transmons detuned by more than their anharmonicities. We experimentally identified zero-$ZZ$ interaction points at qubit-qubit detunings of 409 and 616 MHz from two distinct TFT devices. We then implemented an adiabatic, coupler-flux-biased controlled-Z gate, achieving gate fidelities of 99.64(6)% and 99.68(8)% across the two devices.

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• Optoelectronics
• Quantum benchmarking
• Quantum circuits
• Quantum control
• Quantum gates
• Quantum information with solid state qubits
• Superconducting qubits
• Microwave techniques