Linear and nonlinear spectroscopy from quantum master equations
Linear and nonlinear spectroscopy from quantum master equations
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DOI：
10.1063/1.5006824
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发表时间：
2017-12-28
影响因子：
4.4
通讯作者：
Berkelbach, Timothy C.
中科院分区：
文献类型：
--
作者：
Fetherolf, Jonathan H.;Berkelbach, Timothy C.
本文研究了二阶无时间卷积量子主方程计算多生色团体系线性和非线性光谱的精确性。我们表明，即使是非绝热耦合的系统，TCL 2主方程预测的线性吸收光谱是准确的，在一个非常广泛的参数范围内，远远超出了预期的基础上的微扰性质的方法;非平衡态人口动力学计算与TCL 2相同的参数是显着不太准确。对于三阶（二维）光谱，人口动力学的重要性和违反所谓的量子回归定理降低了TCL 2动力学的准确性。为了纠正这些故障，我们结合联合收割机的TCL 2方法与一个经典的合奏采样缓慢的微观浴自由度，导致一个有效的混合量子经典计划，显示出良好的精度在很宽的参数范围。在光谱设置中，这种混合方案的成功可以通过其均匀和非均匀加宽的单独处理来理解。重要的是，所提出的方法具有TCL 2的计算缩放，适度增加了与集合采样相关的并行前因子。所提出的方法可以理解为一个广义的非均匀累积展开技术，能够处理非绝热动力学的多级系统。由AIP出版社出版。
We investigate the accuracy of the second-order time-convolutionless (TCL2) quantum master equation for the calculation of linear and nonlinear spectroscopies of multichromophore systems. We show that even for systems with non-adiabatic coupling, the TCL2 master equation predicts linear absorption spectra that are accurate over an extremely broad range of parameters and well beyond what would be expected based on the perturbative nature of the approach; non-equilibrium population dynamics calculated with TCL2 for identical parameters are significantly less accurate. For third-order (two-dimensional) spectroscopy, the importance of population dynamics and the violation of the so-called quantum regression theorem degrade the accuracy of TCL2 dynamics. To correct these failures, we combine the TCL2 approach with a classical ensemble sampling of slow microscopic bath degrees of freedom, leading to an efficient hybrid quantum-classical scheme that displays excellent accuracy over a wide range of parameters. In the spectroscopic setting, the success of such a hybrid scheme can be understood through its separate treatment of homogeneous and inhomogeneous broadening. Importantly, the presented approach has the computational scaling of TCL2, with the modest addition of an embarrassingly parallel prefactor associated with ensemble sampling. The presented approach can be understood as a generalized inhomogeneous cumulant expansion technique, capable of treating multilevel systems with non-adiabatic dynamics. Published by AIP Publishing.