Robust Extraction of Tomographic Information via Randomized Benchmarking

We describe how randomized benchmarking can be used to reconstruct the unital
part of any trace-preserving quantum map, which in turn is sufficient for the
full characterization of any unitary evolution, or more generally, any unital
trace-preserving evolution. This approach inherits randomized benchmarking's
robustness to preparation and measurement imperfections, therefore avoiding
systematic errors caused by these imperfections. We also extend these
techniques to efficiently estimate the average fidelity of a quantum map to
unitary maps outside of the Clifford group. The unitaries we consider include
operations commonly used to achieve universal quantum computation in a
fault-tolerant setting. In addition, we rigorously bound the time and sampling
complexities of randomized benchmarking procedures.