Remote entangling gates for spin qubits in quantum dots using a charge-sensitive superconducting coupler

We propose a method to realize microwave-activated cz gates between two remote spin qubits in quantum dots using a charge-sensitive superconducting coupler. The qubits are longitudinally coupled to the coupler, such that the transition frequency of the coupler depends on the logical qubit states; a capacitive network model using first-quantized charge operators is developed to illustrate this. Driving the coupler transition then implements a conditional phase shift on the qubits. Two pulsing schemes are investigated: a rapid, off-resonant pulse with constant amplitude, and a pulse with envelope engineering that incorporates dynamical decoupling to mitigate charge noise. We develop non-Markovian time-domain simulations to accurately model gate performance in the presence of $1/{f}^{\ensuremath{\beta}}$ charge noise. Simulation results indicate that a cz gate fidelity exceeding 90% is possible with realistic parameters and noise models.