High-fidelity entangling gates for fluxonium qubits via flux modulation of a tunable coupler

The enhancement of coherence times in fluxonium qubits renders them an interesting alternative to transmons. To achieve high-fidelity two-qubit gates, here we propose connecting two fluxonia with a tunable coupler. Each fluxonium is galvanically linked to two coupler degrees of freedom, one that is harmonic and the other that is fluxonium like. We show that for this circuit, static ZZ coupling is suppressed and the desired XX coupling can be tuned through zero. We present flux pulses for a √iSWAP gate predicted to achieve fidelities as high as 0.9999 under realistic conditions.