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要旨

We investigate the capability of attosecond transient absorption spectroscopy to characterize the dynamics of inner-shell-excited systems. In the transient absorption spectroscopy setup considered, wave packets are prepared by an attosecond XUV pulse and probed by a femtosecond NIR pulse. By using this, we study coherent electron dynamics in core-excited xenon atoms. In particular, we clarify which aspects of the dynamics can be revealed when the wave packets are probed using an NIR pulse and analyze why the inner-shell hole dynamics is more difficult to probe than the dynamics of the excited electron. We perform a theoretical analysis of the transient absorption signal as a function of the time delay between the XUV pump and NIR probe pulses, treating the excitation pulse perturbatively and the probe pulse nonperturbatively. We also demonstrate that an additional NIR dressing field can dramatically influence the transient absorption spectrum. Our theoretical predictions are compared with experimental results, suggesting that a precise characterization of the NIR pulse is necessary for a qualitative and quantitative comparison.