Attosecond Physics explores ways to follow and control matter with unprecedented temporal resolution (1 attosecond= 10-18 s.). Strong laser fields used to apply forces on the sub-cycle timescale, together with the availability of tabletop attosecond soft x-ray pulses, now open avenues for time-resolving ultrafast dynamics on the unexplored attosecond timescale [1, 2]. In this first attosecond pump - attosecond probe experiment, an isolated 100 eV attosecond pulse initiates an Auger decay followed by an attosecond broadband (250-1100nm) optical pulse. The observable is the soft x-ray absorption spectrum as a function of pump-probe delay. A first experiment in krypton atoms allows us to model the effect of the optical probe as a gate of the Auger electronic dipole, a universal analog to the frequency-resolved optical gating technique . Applying our attosecond x-ray absorption near-edge spectroscopy (AXANES) to the L-edge of fused silica enables us to directly observe and control sub-femtosecond core-excitons in solids, laying the foundation of soft x-ray excitonics.
 J. B. Bertrand et al., Nature Physics 9, 174 (2013).
 S. R. Leone et al., Nature Photonics 8, 162 (2014).
 R. Trebino, FROG, Kluwer Academic Publishers, Boston (2002).
 A. Moulet, J. B. Bertrand, T. Klostermann, A. Guggenmos, N. Karpowicz, E. Goulielmakis, Science 357, 1134-1138 (2017).