Resolve the post-pulse coherent hole ring current

Determine whether the coherent hole ring current persists after the ionizing laser pulse and explain why it has not been observed in prior measurements.

Background

The paper discusses the difficulty of resolving subcycle hole ring-current dynamics in residual ions. Existing detection schemes based on electron spectroscopy or high-harmonic spectroscopy do not provide state-resolved, subcycle tracking of the coherent motion among spin-orbit-split ionic states. Against this background, the authors identify the unresolved status of the coherent ring current after the driving pulse and the unexplained absence of its observation as a specific open issue motivating attosecond circular-dichroism spectroscopy.