Efficient real-time path integrals for non-Markovian spin-boson models
Efficient real-time path integrals for non-Markovian spin-boson models
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DOI：
10.1088/1367-2630/aa8744
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发表时间：
2017-04
影响因子：
3.3
通讯作者：
A. Strathearn;B. Lovett;P. Kirton
中科院分区：
文献类型：
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作者：
A. Strathearn;B. Lovett;P. Kirton
系统与环境之间的强耦合导致了非马尔可夫动力学的出现，这不能用时间-局部主方程来描述。捕捉这种动态的一种方法是使用数值实时路径积分，其中假设有限的洗浴记忆时间能够实现可管理的模拟缩放。然而，通过与精确可溶的独立玻色子模型的比较，我们表明，当使用有限记忆近似时，精确动力学中瞬时负衰减率的存在可以导致密度矩阵元的非物理指数增长。因此，我们重新表述了这一近似，使得精确的动力学是完全相同的，然后将我们的新方法应用于具有超欧姆环境耦合的自旋-玻色子模型，该模型通常用于模拟声子环境，但不能精确求解。我们的新方法允许我们很容易地访问参数制度，在那里我们发现人口动态中的复苏是由于信息从浴缸到系统的非马尔科夫回流。
Strong coupling between a system and its environment leads to the emergence of non-Markovian dynamics, which cannot be described by a time-local master equation. One way to capture such dynamics is to use numerical real-time path integrals, where assuming a finite bath memory time enables manageable simulation scaling. However, by comparing to the exactly soluble independent boson model, we show that the presence of transient negative decay rates in the exact dynamics can result in simulations with unphysical exponential growth of density matrix elements when the finite memory approximation is used. We therefore reformulate this approximation in such a way that the exact dynamics are reproduced identically and then apply our new method to the spin-boson model with superohmic environmental coupling, commonly used to model phonon environments, but which cannot be solved exactly. Our new method allows us to easily access parameter regimes where we find revivals in population dynamics which are due to non-Markovian backflow of information from the bath to the system.