Mixed quantum-classical electrodynamics: Understanding spontaneous decay and zero-point energy
Mixed quantum-classical electrodynamics: Understanding spontaneous decay and zero-point energy
复制标题
DOI：
10.1103/physreva.97.032105
复制
发表时间：
2018-03-12
影响因子：
2.9
通讯作者：
Subotnik, Joseph E.
中科院分区：
文献类型：
--
作者：
Li, Tao E.;Nitzan, Abraham;Subotnik, Joseph E.
通过Maxwell-Liouville方程的半经典传播，针对一维和三维系统显式模拟了与电磁场耦合的电子二能级系统的动力学。我们考虑了三种混合量子-经典动力学：（i）经典路径近似（CPA），（ii）Eschlafest动力学，（iii）对称准经典（SQC）动力学。我们的调查结果如下：（i）CPA未能恢复自发辐射的一致描述，（ii）一致的“自发”发射可以从Eschlafest动力学获得，前提是一个开始在电子叠加态，和（iii）自发辐射总是使用SQC动力学获得。使用SQC和Escherfest框架，我们进一步计算了传入脉冲后的动力学，但在这里我们发现非常不同的响应：SQC和Escherfest动力学有时会在计算的瞬态激发态衰减率中强烈偏离。然而，我们的工作证实了米勒[J. Chem. Phys. 69，2188（1978）]早期的观察，即Escherfest动力学可以有效地描述自发辐射的某些方面，并突出了用半经典力学研究光-物质相互作用的有趣的可能性。
The dynamics of an electronic two-level system coupled to an electromagnetic field are simulated explicitly for one-and three-dimensional systems through semiclassical propagation of the Maxwell-Liouville equations. We consider three flavors of mixed quantum-classical dynamics: (i) the classical path approximation (CPA), (ii) Ehrenfest dynamics, and (iii) symmetrical quasiclassical (SQC) dynamics. Our findings are as follows: (i) The CPA fails to recover a consistent description of spontaneous emission, (ii) a consistent "spontaneous" emission can be obtained from Ehrenfest dynamics, provided that one starts in an electronic superposition state, and (iii) spontaneous emission is always obtained using SQC dynamics. Using the SQC and Ehrenfest frameworks, we further calculate the dynamics following an incoming pulse, but here we find very different responses: SQC and Ehrenfest dynamics deviate sometimes strongly in the calculated rate of decay of the transient excited state. Nevertheless, ourwork confirms the earlier observations by Miller [J. Chem. Phys. 69, 2188 (1978)] that Ehrenfest dynamics can effectively describe some aspects of spontaneous emission and highlights interesting possibilities for studying light-matter interactions with semiclassical mechanics.