The addition of tunable couplers to superconducting quantum architectures offers significant
advantages for scalability compared to fixed coupling approaches. Couplers such as the
one proposed in Ref. allow exact cancellation of qubit-qubit coupling by interfering the
coupling through a capacitor with the coupling through a tunable qubit. However, the
cancellation is necessarily narrowband, and in a multiqubit environment with stray couplings
the cancellation condition can change depending on which gate is operating and even the …