The Hartmann-Hahn technique allows sensitivity enhancement of magnetic resonance imaging and spectroscopy by coupling the spins under study to another spin species that is externally driven. Here we theoretically study the coupled spins' dynamics and find that for a certain region of driving parameters the system becomes unstable. The required conditions for making this region of instability becoming experimentally accessible are discussed.

中文翻译：

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Hartmann-Hahn双共振的不稳定性

Hartmann-Hahn技术通过将研究中的自旋耦合到外部驱动的另一种自旋物种，从而增强了磁共振成像和光谱学的灵敏度。在这里，我们从理论上研究了耦合自旋的动力学，发现对于一定范围的驱动参数，系统变得不稳定。讨论了使该不稳定区域变为实验可访问的必要条件。