标题： CPMG序列在时变磁场中的绝热和非绝热行为观察 显示英文标题

标题： Observation of adiabatic and non-adiabatic behavior for CPMG sequence in time-dependent magnetic fields

摘要： 我们实验研究了时变磁场对Carr-Purcell-Meiboom-Gill (CPMG)序列自旋动力学的影响。 在广泛的偏移磁场和斜率范围内，测量的响应与绝热行为完全一致。 回波幅度表现出与理论预测高度一致的特征调制。 在特定的偏移处观察到非绝热事件。 在通过这些偏移后突然，实验结果偏离理论的绝热表达式。 这些非绝热事件恰好发生在理论上预测的场偏移处。 证明在绝热区域内，场波动的影响是完全可逆的，而非绝热事件的发生会导致滞后效应。 通过修改CPMG序列中的重聚焦脉冲，可以增加场偏移的绝热范围。 显示英文摘要

摘要： We investigate experimentally the effect of time dependent magnetic fields on the spin dynamics of the Carr - Purcell - Meiboom - Gill (CPMG) sequence. Over a wide range of offset fields and ramp rates, the measured response is fully consistent with adiabatic behavior. The echo amplitudes exhibit characteristic modulations that are in excellent agreement with theoretical predictions. Non-adiabatic events are observed at distinct offsets. Abruptly after passing through these offsets, the experimental results deviate from the theoretical adiabatic expressions. These non-adiabatic events occur precisely at the field offsets predicted by theory. It is demonstrated that in the adiabatic regime the effects of field fluctuations are fully reversible, while the occurrence of non-adiabatic events leads to hysteresis. The adiabatic range of field offsets can be increased by modifying the refocusing pulses within the CPMG sequence.