Weak-Coupling Theory for Low-Frequency Periodically Driven Two-Level Systems

We generalize the Wu-Yang strong-coupling theory to solve analytically periodically driven two-level systems in the weak-coupling and low-frequency regimes for single- and multi-period periodic driving of continuous-wave-type and pulse-type including ultrashort pulses of a few cycles. We also derive a general formula of the AC Stark shift suitable for such diverse situations