In this work, we studied the relaxation dynamics of coherences of different orders present in a system of two coupled nuclear spins. We used a previously designed model for intrinsic noise present in such systems which considers the Lindblad master equation for Markovian relaxation. We experimentally created zero-, single- and double-quantum coherences in several two-spin systems and performed a complete state tomography and computed state fidelity. We experimentally measured the decay of zero- and double-quantum coherences in these systems. The experimental data fitted well to a model that considers the main noise channels to be a correlated phase damping (CPD) channel acting simultaneously on both spins in conjunction with a generalised amplitude damping channel acting independently on both spins. The differential relaxation of multiple-quantum coherences can be ascribed to the action of a CPD channel acting simultaneously on both the spins.

中文翻译：

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使用 Lindbladian 方法通过相关相位阻尼和振幅阻尼噪声通道对两个耦合核自旋中的退相干进行建模

在这项工作中，我们研究了两个耦合核自旋系统中存在的不同阶相干性的弛豫动力学。我们使用了先前为此类系统中存在的固有噪声设计的模型，该模型考虑了马尔可夫松弛的 Lindblad 主方程。我们通过实验在几个双自旋系统中创建了零、单和双量子相干性，并执行了完整的状态断层扫描和计算状态保真度。我们通过实验测量了这些系统中零和双量子相干性的衰减。实验数据很好地拟合了一个模型，该模型将主要噪声通道视为同时作用于两个自旋的相关相位阻尼 (CPD) 通道以及独立作用于两个自旋的广义振幅阻尼通道。