Conditional wavefunction approach to the structure and dynamics of many-body systems

The interacting conditional wavefunction approach is a recently introduced method for performing quantum dynamics simulations that is multiconfigurational by construction and that is able to capture quantitative accuracy for situations where mean-field theory fails. The technique is highly parallelizable and reformulates the traditional “curse of dimensionality” by using a stochastic wavefunction ansatz that is based on an interacting set of single-particle conditional wavefunctions. Here, we put forth an imaginary-time version of the method and demonstrate its ability for capturing correlated properties in systems made of interacting electrons and nuclei. This is illustrated for three highly-correlated problems: a model system of electron-Hydrogen scattering, a photo-excited proton-coupled electron transfer problem, and the strong-field ionization dynamics of a model H₂ molecule. These examples highlight the ability of the method to capture electron-electron, electron-nuclear and field-induced correlations respectively. This work paves the way for applications to systems driven out of equilibrium.