Mananga Eugene S, Reid Alicia E
HARVARD UNIVERSITY, HARVARD MEDICAL SCHOOL AND MASSACHUSETTS GENERAL HOSPITAL Center for Advanced Radiological Sciences, Division of Nuclear Medicine and Molecular Imaging Physics Department of Radiology, 55 Fruit Street, Boston, Massachusetts, 02114.
THE CITY UNIVERSITY OF NEW YORK, MEDGAR EVERS COLLEGE, 1638 Bedford Avenue, Brooklyn, NY, 11225.
Mol Phys. 2013;111(2):243-257. doi: 10.1080/00268976.2012.718379.
This paper presents the study of finite pulse widths for the BABA pulse sequence using the Floquet-Magnus expansion (FME) approach. In the FME scheme, the first order is identical to its counterparts in average Hamiltonian theory (AHT) and Floquet theory (FT). However, the timing part in the FME approach is introduced via the () function not present in other schemes. This function provides an easy way for evaluating the spin evolution during "the time in between" through the Magnus expansion of the operator connected to the timing part of the evolution. The evaluation of () is useful especially for the analysis of the non-stroboscopic evolution. Here, the importance of the boundary conditions, which provides a natural choice of (0) is ignored. This work uses the () function to compare the efficiency of the BABA pulse sequence with and the BABA pulse sequence with finite pulses. Calculations of () and are presented.
本文采用弗洛凯 - 马格努斯展开(FME)方法对BABA脉冲序列的有限脉冲宽度进行了研究。在FME方案中,一阶项与平均哈密顿理论(AHT)和弗洛凯理论(FT)中的对应项相同。然而,FME方法中的时间部分是通过其他方案中不存在的()函数引入的。该函数通过与演化时间部分相关的算符的马格努斯展开,为评估“中间时间”的自旋演化提供了一种简便方法。()的评估对于非频闪演化的分析尤为有用。这里,忽略了提供(0)自然选择的边界条件的重要性。这项工作使用()函数来比较具有和具有有限脉冲的BABA脉冲序列的效率。给出了()和的计算结果。