Role of shake-up channels in Neon photoionization time delay

The longstanding controversy surrounding the time delay difference ($21\pm5$~as at 105~eV) measured in the photoionization of neon from the $2s$ and $2p$ shells [1] has been explained in a recent experimental work [2]. As predicted by a past {\it ab initio} study [3], it was shown in [2] that shake-up channels, which were not resolved in [1], were responsible for the discrepancy between theoretical calculations and the experimental data. This new finding, however, rises the question whether the shake-up channel indicated as being responsible for the measurement bias is the dominant one or if other channels might contribute significantly. In this work, we employ the \footnotesize\textsc{NEWSTOCK} {\it ab initio} method to analyze and quantify the effect of shake-up channels above 80~eV photon energy in neon. We also perform realistic XUV-pump-IR-probe time-dependent calculations and compare our results with the experimental data [2]. [1] M. Sch\"{u}ltze {\it et al.} Science {\bf 328} 1658 (2010), [2] M. Isinger {\it et al.} Science {\bf 358} 893 (2017), [3] Feist {\it et al.} PRA {\bf 89} 033417 (2014).