Extended Data Figure 2: Few-level model simulation details.
From: Reconstruction and control of a time-dependent two-electron wave packet
a, Level scheme of the simulated subsystem, including the ground state |g〉 ≡ |1s2〉, the autoionizing bound states |a〉 ≡ |2s2p〉, |b〉 ≡ |2p2〉 and |c〉 ≡ |sp2,3+〉, and the continua |1s, εp〉 and |1s, εs〉, all coupled via the dipole matrix elements dnm as depicted. The configuration-interaction matrix elements Vε,n couple the excited states with their corresponding (symmetry 1Po or 1Se) continua. b, Schrödinger equation describing the temporal evolution of the coupled states’ expansion coefficients cn(t), resulting from the respective coupling pathways depicted in a. Further explanations and definitions of parameters are given in ‘Few-level model simulation’ in Methods. c, Simulated two-dimensional absorbance plot of the few-level system assuming a quasi-monochromatic VIS field of 730 nm wavelength. The absorbance spectra were temporally averaged over one VIS laser cycle (XUV/VIS delay), and convolved with the experimental detector resolution (σ = 20 meV). d–f, Simulated temporal evolution of |cn(t)| of the three autoionizing states 2s2p (1Po; black lines), 2p2 (1Se; blue lines) and sp2,3+ (1Po; red lines) where the 1Po-symmetry states were weakly populated by an XUV attosecond pulse at time t = 0 fs. All states were coupled by a VIS pulse (7 fs, 730 nm, 3 × 1012 W cm−2) at three different time delays τ. The dashed curves show the states’ evolution in the absence of the VIS field.
