Quantum Process Tomography of a Controlled-NOT Gate

作者：Jeremy L. O’Brien, Geoff J. Pryde, Alexei Gilchrist, Daniel F. V. James, Nathan K. Langford, Timothy C. Ralph, Andrew G. White · 发表于：Physical Review Letters · 年份：2004 · DOI：10.1103/physrevlett.93.080502 · 被引用次数：503 · 研究领域：Quantum Information and Cryptography、Quantum Computing Algorithms and Architecture、Quantum Mechanics and Applications

We demonstrate complete characterization of a two-qubit entangling process--a linear optics controlled-NOT gate operating with coincident detection--by quantum process tomography. We use a maximum-likelihood estimation to convert the experimental data into a physical process matrix. The process matrix allows an accurate prediction of the operation of the gate for arbitrary input states and a calculation of gate performance measures such as the average gate fidelity, average purity, and entangling capability of our gate, which are 0.90, 0.83, and 0.73, respectively.