In this paper, we propose to use a quantum speed limit (QSL) as a measure of robustness of states, defining that a state with bigger QSL is more robust. In this perspective, it is important to have an explicitly-computable QSL, because then we can formulate an engineering problem of Hamiltonian that makes a target state robust against decoherence. Hence we derive a new explicitly-computable QSL that is applicable to general Markovian open quantum systems. This QSL is tighter than another explicitly-computable QSL, in an important setup such that decoherence is small. Also the Hamiltonian engineering problem with this QSL is a quadratic convex optimization problem, and thus it is efficiently solvable. The idea of robust state characterization and the Hamiltonian engineering, in terms of QSL, is demonstrated with several examples.

中文翻译：

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用于鲁棒状态表征和工程设计的量子速度限制

在本文中，我们建议使用量子速度限制（QSL）作为状态鲁棒性的度量，从而定义具有更大QSL的状态更鲁棒。从这个角度来看，拥有一个可明确计算的QSL非常重要，因为这样我们就可以提出哈密顿量的工程问题，从而使目标状态具有较强的抗相干性。因此，我们得出了一个适用于一般马尔可夫开放量子系统的新的可明确计算的QSL。在一个重要的设置中，该QSL比另一个可明确计算的QSL更加严格，以至于退相干很小。同样，使用此QSL的汉密尔顿工程问题也是二次凸优化问题，因此可以有效地解决。用几个示例说明了基于QSL的鲁棒状态表征和哈密顿工程学的思想。