标题： 长时行为在可精确求解的纯退相干模型中的研究及马尔可夫嵌入问题 显示英文标题

标题： Long-term behaviour in an exactly solvable model of pure decoherence and the problem of Markovian embedding

摘要： 我们研究了一个著名的可精确求解的开放量子系统纯退相干模型。 本文的目的有两个方面。 首先，退相干是开放量子系统的一个重要性质，对于量子技术以及量子-经典过渡的基本问题都很重要。 研究在这个可精确求解的模型中，退相干的长期速率如何依赖于表征系统-浴相互作用的谱密度是值得的。 其次，我们探讨了非马尔可夫开放系统动力学的马尔可夫嵌入这一更一般的问题。 通常认为一个非马尔可夫开放量子系统可以嵌入到更大的马尔可夫系统中。 然而，我们证明这种嵌入仅对欧姆谱密度（在浴温为正的情况下）是可能的，而对于次欧姆和超欧姆谱密度则是不可能的。 从另一方面来看，对于欧姆谱密度，在大时间尺度上存在马尔可夫性（根据量子回归公式）。 显示英文摘要

摘要： We consider a well-known exactly solvable model of an open quantum system with pure decoherence. The aim of this paper is twofold. Firstly, decoherence is a property of open quantum systems important for both quantum technologies and the fundamental question of quantum-classical transition. It is worthwhile to study how the long-term rate of decoherence depends on the spectral density characterizing the system-bath interaction in this exactly solvable model. Secondly, we address a more general problem of the Markovian embedding of a non-Markovian open system dynamics. It is often assumed that a non-Markovian open quantum system can be embedded into a larger Markovian system. However, we show that such embedding is possible only for the Ohmic spectral densities (for the case of a positive bath temperature) and is impossible for both the sub- and super-Ohmic spectral densities. From the other side, for the Ohmic spectral densities, an asymptotic large-time Markovianity (in terms of the quantum regression formula) takes place.