  The accurate description of the interaction of a quantum system with a its
environment is a challenging problem ubiquitous across all areas of physics,
and lies at the foundation of quantum mechanics theory. Here we pioneer a new
strategy to create discrete low-rank models of the system-environment
interaction, by exploiting the frequency and time domain information encoded in
the fluctuation-dissipation relation connecting the system-bath correlation
function and the spectral density. We demonstrate the effectiveness of our
methodology by combining it with tensor-network methodologies and simulating
the quantum dynamics of a complex excitonic systems in a highly structured
bosonic environment. The new modeling framework sets the basis for a leap in
the analysis of open quantum systems providing controlled accuracy at
significantly reduced computational costs, with benefits in all connected
research areas.
