The similarities observed in Fig. between CTMQC and MTE suggest that, for model A, the mean-field component of the coupling between the photon-nuclear degrees of freedom and the electrons is the leading effect in CTMQC. However, in CTMQC, the coupling of the trajectories, encoded in the quantum momentum, affects both the photon-nuclear and the electronic dynamics. Its effect becomes evident in Fig. , where we show the marginal nuclear densities at times t = 0, 500, 1250 a.t.u. as indicated in the figure, for CTMQC (top panels), MTE (middle panels), and TSH (bottom panels). The superimposed solid black lines are the reference marginal nuclear densities of QD calculations. From the comparison of methods reported in Fig. , it is clear that, even if not with perfect agreement with QD, CTMQC is able to reproduce better the splitting of the marginal nuclear density observed at long times. Finally, note that in model A, there is not significant information to be derived from the photonic marginal density as it remains close to a Gaussian centered at q = 0 throughout the dynamics, providing limited insights.