Attosecond core-level sensitivity to low-energy processes in correlated materials

Determine whether attosecond core-level spectroscopies that utilize extreme-ultraviolet to soft X-ray photons can simultaneously resolve low-energy quasiparticle interactions in strongly correlated materials while capturing attosecond high-energy dynamics, despite their typical focus on localized core-level responses.

Background

Time-resolved core-level spectroscopies offer attosecond temporal resolution by employing broad XUV-to-soft X-ray bandwidths, but their traditional application has centered on high-energy, localized electronic dynamics. The time–energy uncertainty principle raises concerns about whether these techniques can be sufficiently sensitive to meV-scale changes associated with low-energy processes central to strongly correlated systems. The paper motivates addressing this limitation by using attosecond broadband XUV absorption spectroscopy (ABXAS), which provides continuous spectral coverage across tens to hundreds of eV and could, in principle, detect subtle low-energy modifications while resolving ultrafast dynamics.