Non-Markovian effects in an open-system dynamics are usually associated to information backflows from the environment to the system. However, the way these backflows manifest and how to detect them is unclear. A natural approach is to study the backflow in terms of the correlations the evolving system displays with another unperturbed system during the dynamics. In this work, we study the power of this approach to witness non-Markovian dynamics using different correlation measures. We identify simple dynamics where the failure of completely positive divisibility is in one-to-one correspondence with a correlation backflow. We then focus on specific correlation measures, such as those based on entanglement and the mutual information, and identify their strengths and limitations. We conclude with a study of a recently introduced correlation measures based on state distinguishability and see how, for these measures, adding an extra auxiliary system enlarges the set of detectable non-Markovian dynamics.

中文翻译：

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通过相关性见证非马尔可夫动力学

开放系统动力学中的非马尔可夫效应通常与从环境到系统的信息回流相关。但是，这些回流的表现方式和检测方法尚不清楚。一种自然的方法是根据动态过程中不断发展的系统与另一个不受干扰的系统显示的相关性来研究回流。在这项工作中，我们研究了这种方法使用不同的相关度量来见证非马尔可夫动力学的能力。我们确定简单的动力学，其中完全正整除法的失败与相关性回流一一对应。然后，我们将重点放在特定的关联度量上，例如基于纠缠和相互信息的度量，并确定其优势和局限性。