Fig. 4: Nonequilibrium dynamical structure factor and transient quantum Fisher information (QFI).
From: Witnessing light-driven entanglement using time-resolved resonant inelastic X-ray scattering
a Evolution of the dynamical spin structure factor S(q, ω, t) estimated from \({{{{{{{\mathcal{I}}}}}}}}(q,\, {\omega }_{{{{{{{{\rm{i}}}}}}}}}-\omega,\, {\omega }_{{{{{{{{\rm{i}}}}}}}}},\, t)\) by fixing the incident energy at ωi = 1.8th, as in Fig. 2. b Spectral distribution for \(t=-5{t}_{h}^{-1}\), 0, and \(5{t}_{h}^{-1}\), respectively. c Time-dependence of the snapshot quantum Fisher information (QFI) density \({\bar{f}}_{{{{{{{{\rm{Q}}}}}}}}}(q,t)\) (blue curve) evaluated by integrating the instantaneous spectral cuts [e.g., each curve in b] and of the exact QFI (black dashed line). d Time dependence of the QFI density fQ(q, t) (red curve) evaluated by the self-consistent iteration in Eq. (5) and comparison with the exact QFI (black dashed line). The core-hole lifetime for these data is \({\tau }_{{{{{{{{\rm{core}}}}}}}}}=1/3\,{t}_{{{{{{{{\rm{h}}}}}}}}}\), while the momentum transfer is fixed to q = π/6.
