  Conducting precise electronic-vibrational dynamics simulations of molecular
systems poses significant challenges when dealing with realistic environments
composed of numerous vibrational modes. Here, we introduce a technique for the
construction of effective phonon spectral densities that capture accurately
open system dynamics over a finite time interval of interest. When combined
with existing non-perturbative simulation tools, our approach can reduce
significantly the computational costs associated with many-body open system
dynamics.
