  Superconducting flux qubits are promising candidates for the physical
realization of a scalable quantum processor. Indeed, these circuits may have
both a small decoherence rate and a large anharmonicity. These properties
enable the application of fast quantum gates with high fidelity and reduce
scaling limitations due to frequency crowding. The major difficulty of flux
qubits' design consists of controlling precisely their transition energy - the
so-called qubit gap - while keeping long and reproducible relaxation times.
Solving this problem is challenging and requires extremely good control of
e-beam lithography, oxidation parameters of the junctions and sample surface.
Here we present measurements of a large batch of flux qubits and demonstrate a
high level of reproducibility and control of qubit gaps, relaxation times and
pure echo dephasing times. These results open the way for potential
applications in the fields of quantum hybrid circuits and quantum computation.
