  Significant experimental advances in single-electron silicon spin qubits have
opened the possibility of realizing long-range entangling gates mediated by
microwave photons. Recently proposed iSWAP gates, however, require tuning qubit
energies into resonance and have limited fidelity due to charge noise. We
present a novel photon-mediated cross-resonance gate that is consistent with
realistic experimental capabilities and requires no resonant tuning.
Furthermore, we propose gate sequences capable of suppressing errors due to
quasistatic noise for both the cross-resonance and iSWAP gates.
