Optically- and thermally-induced electronic transitions in a three-level system
Optically- and thermally-induced electronic transitions in a three-level system
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DOI：
10.1088/1402-4896/abb85e
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发表时间：
2020-09
期刊：
影响因子：
2.9
通讯作者：
Mingyang Qiu;W. Jin;S. Qu;Chun Li;G. Lefkidis;W. Huebner
中科院分区：
文献类型：
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作者：
Mingyang Qiu;W. Jin;S. Qu;Chun Li;G. Lefkidis;W. Huebner
在本文中，我们使用 Lindblad 超级算子形式，研究了与外部热浴耦合的三能级模型系统中激光诱导的 Λ 过程的电子跃迁。我们发现，对于从初始状态到最终状态的布居转移，当热跃迁的两个分支（即初始到中间状态和中间到最终状态）对称时，不平衡的光通道可以增强动力学的保真度。特别是在两个光分支之一被完全禁止的情况下，由于热跃迁通道的补偿，保真度仍然达到最大值，导致布居俘获在最终状态（热辅助Λ过程）。另一方面，在对称光学跃迁的情况下，随着不平衡热通道的增加，过程的保真度不会改变，但动力学达到稳态的速度减慢。此外，我们研究并分析了浴温度、热浴耦合常数以及最终状态随时间变化的能量变化的作用。最后一个方面，通过详细的对称性分析，介绍了其在实际 Ni2 分子上的应用。预计结果将与室温下真实纳米自旋电子器件中自旋的主动操纵高度相关。
In this article , using the Lindblad-superoperator formalism, we study the laser-induced electronic transitions of a Λ process in a three-level model system coupled to an external thermal bath. We find that, with respect to the population transfer from the initial to the final state, when the two branches of the thermal transitions (i.e., initial to intermediate state and intermediate to final state) are symmetric, the unbalanced optical channels can enhance the fidelity of the dynamics. Especially for the case where one of the two optical branches is totally forbidden, the fidelity still reaches the maximal value due to the compensation by the thermal transition channel, leading to a population trapping in the final state (thermally assisted Λ process). On the other hand, with the increase of the unbalanced thermal channels in the case of symmetric optical transitions, the fidelity of the process does not change but the speed for the dynamics to reach the steady state slows down. Additionally, we investigate and analyze the role of the bath temperature, of the coupling constant to the thermal bath, as well as of a time-dependent energy shifting of the final state. For the last aspect, followed by the detailed symmetry analysis, its application on a realistic Ni2 molecule is presented. The results are expected to be highly relevant to the active manipulation of spins in real nanospintronic devices at room temperature.