Theoretical Physics, Universität des Saarlandes, D-66123 Saarbrücken, Germany.
Phys Rev Lett. 2014 Jun 20;112(24):240503. doi: 10.1103/PhysRevLett.112.240503.
Optimal quantum control theory carries a huge promise for quantum technology. Its experimental application, however, is often hindered by imprecise knowledge of the input variables, the quantum system's parameters. We show how to overcome this by adaptive hybrid optimal control, using a protocol named Ad-HOC. This protocol combines open- and closed-loop optimal control by first performing a gradient search towards a near-optimal control pulse and then an experimental fidelity estimation with a gradient-free method. For typical settings in solid-state quantum information processing, adaptive hybrid optimal control enhances gate fidelities by an order of magnitude, making optimal control theory applicable and useful.
最优量子控制理论为量子技术带来了巨大的希望。然而，其实验应用常常受到输入变量和量子系统参数的不精确知识的限制。我们展示了如何通过自适应混合最优控制来克服这一问题，使用一种名为 Ad-HOC 的协议。该协议通过首先执行一个接近最优的控制脉冲的梯度搜索，然后使用无梯度方法进行实验保真度估计，将开环和闭环最优控制结合起来。对于固态量子信息处理中的典型设置，自适应混合最优控制将门保真度提高了一个数量级，从而使最优控制理论变得可行和有用。
