Attosecond electronic dynamics in atoms

We study the complex coherent dynamics proceeding on a time scale comparable to that of the duration of the sub-fs XUV excitation. A prototype case for the coherent dynamics in a non-stationary system is the excitation of a Fano resonance resulting from the interference between the direct pathway to the continuum and the indirect path via quasi-bound states embedded in the continuum. We have shown that such a time evolution can be mapped out by an attosecond streaking technique in a pump-probe setting provided that the time scale of the XUV pulse, of the lifetime of the resonance, and of the probe pulse are comparable to each other