Abstract

We study the real-time dynamics of a periodic XY system exposed to a composite field comprised of a constant homogeneous magnetic and a quantized circularly polarized electromagnetic fields. The interaction between the quantized mode and spin-magnetic moments is modeled by the Dicke Hamiltonian. The rotating wave approximation is applied and the conditions for its validity are discussed. It is shown that if initially all of the excitations are contained in the field, then in the regime of large detuning, the main evolutionary effect involves oscillations of the excitations between the zero-momentum modes of the chain and the field. Accordingly, the reduced photon number and magnetization per site reveal a sort of oscillatory behavior. Effective Hamiltonians describing the short-time dynamics of the present model for small number of excitations and large detuning are introduced. The resonance case is considered in the context of photon emission from the chain initially prepared in the (partially) excited state. In particular, it is demonstrated, in the framework of a specific example, that the superradiant behavior shows up at the beginning of the emission, when we have an initial state with a maximally excited XY chain. Possible applications of the model to problems such as spin chain and J-aggregate in a single-mode cavity are discussed.

Graphical abstract

中文翻译：

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耦合到光子模式的周期性XY链的动力学

摘要

我们研究周期性XY的实时动力学暴露于由恒定均质磁场和量化圆极化电磁场组成的复合场的系统。量子模和自旋磁矩之间的相互作用是由迪克·汉密尔顿（Dicke Hamiltonian）建模的。应用了旋转波近似，并讨论了其有效性的条件。结果表明，如果最初所有的激发都包含在磁场中，那么在大的失谐状态下，主要的演化效应涉及链的零动量模态与磁场之间的激发振荡。因此，减少的每个位置的光子数和磁化强度揭示了一种振荡行为。介绍了有效的哈密顿量，该哈密顿量描述了当前模型的少量激励和大失谐的短期动力学。在最初以（部分）激发态制备的链的光子发射中考虑了共振情况。特别是，在一个具体示例的框架中证明，当我们具有最大激发的初始状态时，超辐射行为会在发射开始时出现。XY链。讨论了该模型在诸如单模腔中的自旋链和J聚集等问题上的可能应用。

图形概要