  We study the robustness of the evolution of a quantum system against small
uncontrolled variations in parameters in the Hamiltonian. We show that the
fidelity susceptibility, which quantifies the perturbative error to leading
order, can be expressed in superoperator form and use this to derive control
pulses which are robust to any class of systematic unknown errors. The proposed
optimal control protocol is equivalent to searching for a sequence of unitaries
that mimics the first-order moments of the Haar distribution, i.e. it
constitutes a 1-design. We highlight the power of our results for error
resistant single- and two-qubit gates.
