结构化声子库中声子诱导的自旋弛豫理论
Theory of phonon-induced spin relaxation in a structured phononic reservoir
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- Institute of Theoretical Physics, Wrocław University of Science and Technology（弗罗茨瓦夫科技大学理论物理研究所）
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中文总结 AI 辅助
研究结构化声子库中电子自旋弛豫，结合量子系统理论与有限元模拟，以量子点为例，发现其自旋弛豫比体材料复杂，弛豫率有高有低，边界处有奇点，发展幂律标度与非马尔可夫描述，揭示极化子修饰。
中文摘要 AI 辅助
通过将马尔可夫和非马尔可夫开放量子系统理论与有限元模拟相结合，我们发展了一种结构化声子库中电子自旋弛豫的理论。该问题对于理解涉及机械模式的混合系统中的自旋动力学至关重要，对于结合自旋自由度与光子和声子架构的器件设计也很关键，在适度磁场对应的相关光谱范围内声子态密度会被调制。以声子波导中的量子点为例，我们表明这种环境中的自旋弛豫比在体材料中复杂得多。虽然弛豫率通常比体材料中高一个数量级，但由于模式色散间隙和模式对称性施加的选择规则，存在参数窗口使弛豫被抑制多个数量级。在这两个区域的边界，声子色散中的范霍夫奇点导致弛豫率出现奇点，我们为此发展了幂律标度并提出动力学的非马尔可夫描述，揭示了自旋到慢声学模式的极化子修饰。
英文摘要
By combining Markovian and non-Markovian open quantum system theory with finite-element simulations, we develop a theory of electron spin relaxation in a structured phononic reservoir. This problem is crucial for understanding spin dynamics in hybrid systems involving mechanical modes, as well as for the design of devices combining spin degrees of freedom with photonic and phononic architectures, where the phonon density of states is modulated in the relevant spectral range corresponding to moderate magnetic fields. Taking a QD in a phononic waveguide as a representative and technologically relevant example, we show that spin relaxation in such environments is much more complex than in bulk. While the relaxation rates are several times to an order of magnitude higher than in bulk, there are parameter windows where the relaxation is suppressed by many orders of magnitude due to gaps in mode dispersion and selection rules imposed by mode symmetry. At the border between these two sectors, van Hove singularities in phonon dispersion lead to singularities in relaxation rates, for which we develop power-law scaling and develop a non-Markovian description of the dynamics, revealing polaronic dressing of the spin into slow acoustic modes.
