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arXiv · 1701.01198

Enhancing quantum control by bootstrapping a quantum processor of 12 qubits

Dawei Lu·Keren Li·Jun Li·Hemant Katiyar·Annie Jihyun Park·Guanru Feng·Tao Xin·Hang Li·GuiLu Long·Aharon Brodutch·Jonathan Baugh·Bei Zeng·Raymond Laflamme
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Abstract

Accurate and efficient control of quantum systems is one of the central challenges for quantum information processing. Current state-of-the-art experiments rarely go beyond 10 qubits and in most cases demonstrate only limited control. Here we demonstrate control of a 12-qubit system, and show that the system can be employed as a quantum processor to optimize its own control sequence by using measurement-based feedback control (MQFC). The final product is a control sequence for a complex 12-qubit task: preparation of a 12-coherent state. The control sequence is about 10% more accurate than the one generated by the standard (classical) technique, showing that MQFC can correct for unknown imperfections. Apart from demonstrating a high level of control over a relatively large system, our results show that even at the 12-qubit level, a quantum processor can be a useful lab instrument. As an extension of our work, we propose a method for combining the MQFC technique with a twirling protocol, to optimize the control sequence that produces a desired Clifford gate.

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Dawei Lu, Keren Li, Jun Li, Hemant Katiyar, Annie Jihyun Park, Guanru Feng, Tao Xin, Hang Li, GuiLu Long, Aharon Brodutch, Jonathan Baugh, Bei Zeng, Raymond Laflamme. 2017-01-05. Enhancing quantum control by bootstrapping a quantum processor of 12 qubits. https://doi.org/10.1038/s41534-017-0045-z

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