AI 中文总结
本研究探讨洛伦兹时间包络场对两态量子系统的相干激发，利用合流Heun函数求解微分方程，通过DDP方法分析跃迁概率，揭示共振奇π脉冲的功率窄化特性。
AI 中文摘要
我们研究具有洛伦兹时间包络和恒定载波频率的场对两态量子系统的相干激发。相关微分方程可通过合流Heun函数获得精确局域表示。针对跃迁概率，我们基于两个相关复跃迁点及其干涉，建立了Dykhne-Davis-Pechukas（DDP）描述。直接分析弱耦合与强耦合极限下的DDP作用量，得到振荡相位、振荡包络、远失谐线形及近共振行为的显式渐近表达式。特别地，强耦合渐近表明，对于共振奇π脉冲，线宽与峰值拉比频率的倒数成正比，从而展现出洛伦兹脉冲的功率窄化特性。
英文摘要
We study the coherent excitation of a two-state quantum system by a field with a Lorentzian temporal envelope and constant carrier frequency. The associated differential equation admits an exact local representation in terms of confluent Heun functions. For the transition probability we develop a Dykhne-Davis-Pechukas (DDP) description based on the two relevant complex transition points and their interference. The DDP action is analyzed directly in the weak- and strong-coupling limits, yielding explicit asymptotic expressions for the oscillation phase, oscillation envelope, far-detuned line shape, and near-resonant behavior. In particular, the strong-coupling asymptotics imply a linewidth proportional to the inverse peak Rabi frequency for resonant odd-$π$ pulses, thereby exhibiting the power-narrowing characteristic of the Lorentzian pulse.
Comments14 pages, 5 figures
