by expressing the full wavefunction as the product of a marginal amplitude, i.e., χ(X,t), and a conditional amplitude, i.e., Φ(x,t; X), that parametrically depends on the coordinates X. The interpretation of |Ψ(x, X,t)| 2 as a joint probability density allows one to easily identify |χ(X,t)| 2 as the marginal probability density of X, with |Φ(x,t; X)| 2 the conditional probability density, whose normalization over x has to be imposed ∀ X,t. The TDSE combined with such a partial normalization condition