Application of Floquet-Magnus and Fer expansion approaches during spin-locking radiation in solid-state NMR

Abstract

We apply and compare two potential expansion schemes that are developing in the field of NMR, namely, the Floquet-Magnus and Fer expansions. We use these expansion schemes for the calculation of effective Hamiltonians and propagators. We present an important iterative approach for the Floquet-Magnus expansion. While both approaches are powerful methods, there are subtle differences among them. To understand these differences, we performed explicit calculations for the multiple-pulse spin-locking experiment. Our work unifies and generalizes existing results of Floquet-Magnus and Fer approaches and delivers illustrations of novel springs that boost previous applications that are based on the classical information.