Novel Methods for High Resolution NMR Spectroscopy in Inhomogeneous Fields

Navin Khaneja教授和他的团队在哈佛大学化学系的分析和表面化学项目的支持下，与慕尼黑工业大学的Steffen Glaser教授合作，开发了在非均匀静态和射频场中进行高分辨率核磁共振（NMR）光谱的新方法。这项工作采用了新颖的射频脉冲序列和梯度波形设计，在材料科学、化学工程和地球科学的移动和非原位核磁共振应用中实现了高分辨率核磁共振。系统地使用控制理论方法可以产生脉冲序列设计，它比传统方法可以获得的脉冲序列设计要短得多，但却提供了相当的补偿性能。这些最佳的设计有助于减少松弛损失，总是存在，从而提高灵敏度。这项国际合作（由德国科学基金会- DFG支持的德国部分）为学生和博士后提供了难得的机会，将核磁共振的理论和实验概念结合起来，再加上广泛的国际合作经验。在这项工作中开发的方法有望广泛适用于其他相干光谱和量子信息科学和相干控制领域。

Professor Navin Khaneja and his group at Harvard University are supported by the Analytical and Surface Chemistry Program in the Division of Chemistry for a collaboration with Professor Steffen Glaser at the Technical University of Munich to develop novel methods for high resolution nuclear magnetic resonance (NMR) spectroscopy in inhomogeneous static and radio-frequency fields. The work employs novel radio-frequency pulse sequences and gradient waveform designs to enable high resolution NMR in mobile and ex-situ NMR applications in materials science, chemical engineering, and geosciences. Systematic use of methods of control theory can generate pulse sequence designs that are significantly shorter than those accessible by conventional methods but offer comparable compensation performance. These optimal designs help to minimize relaxation losses that are always present and thereby improve the sensitivity. This international collaboration (with the German portion supported by the German Science Foundation - DFG) provides students and postdocs with exceptional opportunities to pair theoretical and experimental concepts of NMR, plus broad experience in international collaboration. The methods developed in this work are expected to be broadly applicable to other coherent spectroscopies and areas of quantum information science and coherent control.