where the term in square brackets is the classical momentum P ν , that depends on the TDVP as anticipated above, and it is summed to the quantum momentum Q ν , and encodes information about the spatial (de)localization of the nuclear density. The non-local nature of this quantity implies that the exact-factorization trajectory-based schemes require coupling among the trajectories, something which is completely overlooked in independent-trajectory schemes, such as TSH or Ehrenfest.