Demonstration of robust quantum gate tomography via randomized benchmarking. (5th November 2015)

• Record Type: Journal Article
• Authors: Johnson, Blake R; Silva, Marcus P da; Ryan, Colm A; Kimmel, Shelby; Chow, Jerry M; Ohki, Thomas A
• Is Part Of: New journal of physics. Volume 17:Number 11(2015:Nov.)
• Publication Date: 2015-11-05
• Subjects: tomography -- quantum information processing -- superconducting qubits -- randomized benchmarking -- quantum computing -- quantum control; Physics -- Periodicals; Physics; Periodicals; 530.05
• DOI: 10.1088/1367-2630/17/11/113019
• Languages: English
• ISSNs: 1367-2630

Abstract

Abstract: 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 RB.