Title: Spin Resonance in Perspective of Floquet Theory and Brillouin-Wigner Perturbation Method Show Chinese title

Title: 自旋共振的弗洛凯理论与布里渊-威纳微扰方法视角

Abstract: We studied the two-level spin resonance in a new perspective. Using the Floquet theory, the periodic interaction Hamiltonians were transfromed into a time-independent interaction. Using the Brillouin-Wigner perturbation method, a degenerated subspace is constructed, where the effective Hamiltonian is given in a perturbation expansion. In this framework, we found that the upper triangular element $\langle \alpha | H^1 | \beta \rangle$, determines whether the resonance happens. The generalized Rabi frequency and the Bloch-Siegert shift were solved straightforwardly as the first order and the second order solution, proving the benefit of the developed method. Show Chinese abstract

Abstract: 我们从新的角度研究了两能级自旋共振。 利用弗洛凯理论，周期性相互作用哈密顿量被转换为时间独立的相互作用。 利用布里渊-维格纳微扰方法，构建了一个简并子空间，在其中给出了有效哈密顿量的微扰展开。 在此框架下，我们发现上三角元素$\langle \alpha | H^1 | \beta \rangle$决定了共振是否发生。 广义拉比频率和布洛赫-西格伯特位移被直接求解为一阶和二阶解，证明了所开发方法的优势。