Quantum steering is the central resource for one-sided device-independent quantum information. It is manipulated via one-way local operations and classical communication, such as local filtering on the trusted party. Here, we provide a necessary and sufficient condition for a steering assemblage to be transformable into another one via local filtering. We characterize the equivalence classes with respect to filters in terms of the steering equivalent observables measurement assemblage (SEO), first proposed to connect the problem of steerability with measurement incompatibility. We provide an efficient method to compute the maximal extractable steerability via local filters and show that it coincides with the incompatibility of the SEO. Moreover, we show that there always exists a bipartite state that provides an assemblage with steerability equal to the incompatibility of the measurements on the untrusted party. Finally, we investigate the optimal success probability and rates for transformation protocols (distillation and dilution) in the single-shot scenario together with examples.
Natural Framework for Device-Independent Quantification of Quantum Steerability, Measurement Incompatibility, and Self-Testing
我们引入装配矩矩阵的概念，即，期望值矩阵的集合，每个期望值与在转向实验中获得的条件量子态相关联。我们演示了它如何以与设备无关的方式用于量子态和测量表征，即，而不需要对测量或制备装置进行任何假设。具体来说，我们展示了如何使用该方法直接从测量结果之间的相关性来降低底层量子态的可操纵性。将这种与设备无关的定量与Piani和Watrous建立的早期结果相结合[Phys. Rev. Lett. 114，060404（2015）]，我们的方法立即提供了关于纠缠的广义鲁棒性的与设备无关的下限，以及潜在的量子态对于一种类型的子信道鉴别问题的有用性。此外，通过证明转向鲁棒性和最近推出的不相容鲁棒性之间的定量关系，我们的方法还允许在Bell型实验中进行的各种测量之间的不相容性的设备独立的量化。明确的例子，这样的界限提供了一种自我测试的执行测量。
Quantifying randomness with measurement incompatibility
Uppsala University（乌普萨拉大学）；KTH Royal Institute of Technology and Stockholm University（瑞典皇家理工学院和斯德哥尔摩大学）；Leibniz Universität Hannover（汉诺威莱布尼茨大学）；University of Jyväskylä（于韦斯屈莱大学）
Faithful certification of steering- and incompatibility-breaking channels
National Chung Hsing University（国立中兴大学）；Technische Universität München（慕尼黑工业大学）；National Center for Theoretical Sciences（国家理论科学中心）；National Cheng Kung University（国立成功大学）
