Appears in collection : Observability and estimation in quantum dynamics

Characterizing quantum processes is a key task for the development of quantum technologies, especially at the noisy intermediate scale of today’s devices. One method for characterizing processes is randomized benchmarking, which is robust against state preparation and measurement (SPAM) errors. A complementing approach asks for full tomographic knowledge. Compressed sensing techniques achieve full tomography of quantum channels essentially at optimal resource efficiency. We attempt to combine the favorable features of both worlds: For multi-qubit unitary gates, we provide a practical (full) tomography method that works with an essentially optimal number of average gate fidelities measured with respect to random Clifford unitaries.