Event DetailsEvent Dates: Friday, June 12, 2015 - 11:00amSeminar Location: JILA X317Speaker Name(s): Professor Alfred MaquetSpeaker Affiliation(s): Laboratoire de Chimie Physique-Matiere et Rayonnement Universite Pierre et Marie Curie Seminar Type/SubjectScientific Seminar Type: JILA Public SeminarEvent Details & Abstract: Attosecond delays in the photoionization of atomic states have been evidenced in experiments performed in the 2010’s. The delays were observed when recording the emission of photoelectron wave packets ejected from different atomic states, in the combined presence of attosecond pulses of XUV radiation and of a synchronized IR laser femtosecond pulse, the latter being used as a reference “clock”. Theoretical treatments were able to relate the measured delays to the energy derivative of the phase-shift attached to the continuum wave functions of the photoelectrons. In spite of persistent discrepancies between theory and experiments, it was a convincing illustration of the validity of Wigner’s "time delay" concept. Attention has recently shifted towards the case of resonant photoionization in the course of which the XUV frequency is tuned close to a resonance of the target system. The case of a transition towards an autoionizing state is particularly interesting as it makes evident the role of electronic correlations. Here, we shall present recent advances realized in the theoretical interpretation of this new class of experiments.