School of Chemistry, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom.
School of Chemistry and School of Physics and Astronomy, University of Leeds, Leeds LS2 9JT, United Kingdom.
J Chem Phys. 2019 Nov 7;151(17):174112. doi: 10.1063/1.5119300.
Non-Markovian effects in open quantum systems are central to understanding spectral lineshape. Here, we quantify the non-Markovianity associated with both overdamped and underdamped vibrations in terms of information flow between the bath and the system and compare this with the broadening and ellipticity of two-dimensional spectra. Using the Breuer Laine Piilo (BLP) measure, we link the well-known stochastic models for spectral lineshape with modern quantum information theory. Specifically, we study the effect of non-Markovianity in a system in contact with underdamped vibrations and examine the differences observed on increasing the damping to the overdamped limit. The open quantum system dynamics are evolved using the hierarchical equations of motion, efficiently terminated with a Markovian cutoff, where separate hierarchies are derived for the underdamped and overdamped environments. It is shown that the BLP measure is quantitatively correlated with the ellipticity of two-dimensional spectra and memory effects are more pronounced in underdamped environments, due to the long-lived feedback of information between the system and its bath, compared to overdamped environments. Environmental signatures in spectral lineshapes emerge as a result of information flow from the bath back into the system.
非马尔可夫效应在开放量子系统中对于理解谱线形状起着核心作用。在这里，我们根据浴和系统之间的信息流来量化与过阻尼和欠阻尼振动相关的非马尔可夫性，并将其与二维谱的展宽和椭圆度进行比较。我们使用 Breuer Laine Piilo (BLP) 测度将熟知的谱线形状随机模型与现代量子信息理论联系起来。具体来说，我们研究了与欠阻尼振动接触的系统中的非马尔可夫性，并考察了在增加阻尼到过阻尼极限时观察到的差异。使用分层运动方程来演化开放量子系统动力学，通过有效的马尔可夫截止来终止，其中为欠阻尼和过阻尼环境分别推导出了单独的层次结构。结果表明，BLP 测度与二维谱的椭圆度定量相关，并且由于系统与其浴之间的信息长时间反馈，与过阻尼环境相比，欠阻尼环境中的记忆效应更为明显。由于从浴到系统的信息流，在谱线形状中出现了环境特征。
