%0 Journal Article
%J New Journal of Physics
%D 2015
%T Demonstration of Robust Quantum Gate Tomography via Randomized Benchmarking
%A Blake R. Johnson
%A Marcus P. da Silva
%A Colm A. Ryan
%A Shelby Kimmel
%A Jerry M. Chow
%A Thomas A. Ohki
%X Typical quantum gate tomography protocols struggle with a self-consistency problem: the gate operation cannot be reconstructed without knowledge of the initial state and final measurement, but such knowledge cannot be obtained without well-characterized gates. A recently proposed technique, known as randomized benchmarking tomography (RBT), sidesteps this self-consistency problem by designing experiments to be insensitive to preparation and measurement imperfections. We implement this proposal in a superconducting qubit system, using a number of experimental improvements including implementing each of the elements of the Clifford group in single `atomic' pulses and custom control hardware to enable large overhead protocols. We show a robust reconstruction of several single-qubit quantum gates, including a unitary outside the Clifford group. We demonstrate that RBT yields physical gate reconstructions that are consistent with fidelities obtained by randomized benchmarking.
%B New Journal of Physics
%V 17
%P 113019
%8 2015/11/05
%G eng
%U http://arxiv.org/abs/1505.06686
%N 11
%R 10.1088/1367-2630/17/11/113019
%0 Journal Article
%J Physical Review X
%D 2014
%T Robust Extraction of Tomographic Information via Randomized Benchmarking
%A Shelby Kimmel
%A Marcus P. da Silva
%A Colm A. Ryan
%A Blake R. Johnson
%A Thomas Ohki
%X 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.
%B Physical Review X
%V 4
%8 2014/3/25
%G eng
%U http://arxiv.org/abs/1306.2348v1
%N 1
%! Phys. Rev. X
%R 10.1103/PhysRevX.4.011050