Pulse excitation to continuous-wave excitation in a low-dimensional interacting quantum system
Real-time dynamics in one-dimensional transverse Ising model coupled with the time-dependent oscillating field is analyzed by using the infinite time-evolving block decimation algorithm and the Floquet theory. In particular, the transient dynamics induced by the pulse field and their connections to the dynamics by a continuous-wave field are focused on. During the pulse-field irradiation, the order parameter shows a characteristic oscillation, in which the frequency shifts from the pulse-field frequency. This is considered as a kind of the Rabi oscillation, but the frequency strongly depends on the intersite Ising interaction. After turning off the pulse field, the oscillation remains with a frequency $\mathit{\Omega}$ and a damping constant $\gamma$. In the case of low fluence, both $\mathit{\Omega}$ and $\gamma$ are scaled by the pulse amplitude in a wide range of the parameter values of the model. In the case of high fluence, $\mathit{\Omega}$ and $\gamma$ are arranged by a product of the pulse amplitude and the pulse width. This implies that the dynamics after turning off the pulse field are decided by a population of the excited state when the pulse field is turned off.