Coupling function from bath density of states

Modelling of an open quantum system requires knowledge parameters that specify how it couples to its environment. However, beyond relaxation rates, realistic for specific environments and materials are rarely known. Here we present a method inferring the coupling between generic bosonic (e.g., phononic) environment from experimentally measurable density states (DOS). With confirm DOS well-known Debye model three-dimensional solids is physically equivalent choosing Ohmic bath. We further match real phonon series Lorentzian functions, allowing us determine gold, yttrium iron garnet (YIG) as examples. The results illustrate obtain material-specific dynamical properties, such memory kernels. proposed opens door more accurate modelling dynamics, example phonon-dominated spin damping in magnetic materials.