Fig. 4: Calculations of the asymmetry and the von Neumann entropy.
From: Entanglement and electronic coherence in attosecond molecular photoionization
a, Asymmetry (black) and von Neumann entropy (red) as a function of the H+ fragment KER (indicated in each plot) and τXUV–NIR for two different values of τXUV–XUV, namely τXUV–XUV = TNIR (solid lines) and \({\tau }_{{\rm{XUV}}-{\rm{XUV}}}=\frac{3}{2}{T}_{{\rm{NIR}}}\) (dashed lines), in which TNIR is the optical period of the NIR laser. b, Asymmetry (black) and von Neumann entropy (red) as a function of the H+ fragment KER (indicated in each plot) and τXUV–XUV for a fixed value of τXUV–NIR, namely, τXUV–NIR = 2.00 fs (KER = 1 eV), 2.10 fs (KER = 3 eV), 2.40 fs (KER = 5 eV), 2.90 fs (KER = 7 eV), 2.70 fs (KER = 9 eV), 2.30 fs (KER = 11 eV), 3.00 fs (KER = 13 eV) and 2.95 fs (KER = 15 eV). c,d, Asymmetry (c) and von Neumann entropy (d) as a function of τXUV–XUV and τXUV–NIR for a H+ KER of 9.924 eV. The black lines that are superimposed with slopes +2 and −2 pass through the maxima in the von Neumann entropy shown in d; the horizontal white lines correspond to \({\tau }_{{\rm{XUV}}-{\rm{XUV}}}=M\frac{{T}_{{\rm{NIR}}}}{2}\) with M = 1–6. c and d are plotted on a linear colour scale over a range indicated at the top left.
