Procedure for improving cross-resonance noise resistance using
  pulse-level control
Current implementations of superconducting qubits are often limited by the
low fidelities of multi-qubit gates. We present a reproducible and
runtime-efficient pulse-level approach for calibrating an improved
cross-resonance gate CR($\theta$) for arbitrary $\theta$. This CR($\theta$)
gate can be used to produce a wide range of other two-qubit gates via the
application of standard single-qubit gates. By performing an interleaved
randomised benchmarking experiment, we demonstrate that our approach leads to a
significantly higher noise resistance than the circuit-level approach currently
used by IBM. Hence, our procedure provides a genuine improvement for
applications where noise remains a limiting factor.
David Danin Felix Tennie