Pulse excitation to continuous-wave excitation in a low-dimensional interacting quantum system

Real-time dynamics in a one-dimensional transverse Ising model coupled with the time-dependent oscillating field is analyzed by using the infinite time-evolving block decimation algorithm and 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 Ω and a damping constant γ. In the case of low fluence, both Ω and γ are scaled by the pulse amplitude over a wide range of the parameter values of the model. In the case of high fluence, Ω and γ are arranged by a product of the pulse amplitude and the pulse width, which governs the population of the excited state when the pulse field is turned off. Experimental feasibility of the present results is briefly discussed.