Randomized benchmarking of single- and multi-qubit control in liquid-state NMR quantum information processing

作者：C A Ryan, M Laforest, R Laflamme · 发表于：New Journal of Physics · 年份：2009 · DOI：10.1088/1367-2630/11/1/013034 · 被引用次数：104 · 研究领域：Quantum Information and Cryptography、Quantum Computing Algorithms and Architecture、Advanced NMR Techniques and Applications

Being able to quantify the level of coherent control in a proposed device implementing a quantum information processor (QIP) is an important task for both comparing different devices and assessing a device's prospects with regards to achieving fault-tolerant quantum control. We implement in a liquid-state nuclear magnetic resonance QIP the randomized benchmarking protocol presented by Knill et al (2008 Phys. Rev. A 77 012307). We report an error per randomized π/2 pulse of 1.3±0.1 × 10 −4 with a single-qubit QIP and show an experimentally relevant error model where the randomized benchmarking gives a signature fidelity decay which is not possible to interpret as a single error per gate. We explore and experimentally investigate multi-qubit extensions of this protocol and report an average error rate for one- and two-qubit gates of 4.7±0.3 × 10 −3 for a three-qubit QIP. We estimate that these error rates are still not decoherence limited and thus can be improved with modifications to the control hardware and software.