2013/10/31 by Colm A. Ryan, Blake R. Johnson, Jay M. Gambetta +4 · 1 citation
Physics and Astronomy · #quant-ph
paper · pdf · doi:10.1103/physreva.91.022118
published as Phys. Rev. A 91, 022118 (2015) · 7 pages, 5 figures; updated references
arxiv created 2013/12/20 · arxiv updated 2015/03/04
We present methods and results of shot-by-shot correlation of noisy measurements to extract entangled state and process tomography in a superconducting qubit architecture. We show that averaging continuous values, rather than counting discrete thresholded values, is a valid tomographic strategy and is in fact the better choice in the low signal-to-noise regime. We show that the effort to measure N-body correlations from individual measurements scales exponentially with N, but with sufficient signal-to-noise the approach remains viable for few-body correlations. We provide a new protocol to optimally account for the transient behavior of pulsed measurements. Despite single-shot measurement fidelity that is less than perfect, we demonstrate appropriate processing to extract and verify entangled states and processes.