greenWTE - Frequency-domain solver for the phonon Wigner Transport Equation with arbitrary heating using Green’s functions
greenWTE is a Python package to solve the Wigner Transport Equation (WTE) in spatial and temporal Fourier space for arbitrary source terms. This allows to compute thermal conductivities from bulk to nanoscale, from static to high frequency regimes. Beyond that it can be used to study the response of materials to arbitrary heat sources. A showcase of the capabilities of greenWTE can be found in the arXiv preprint “Transition from Population to Coherence-dominated Non-diffusive Thermal Transport” [arXiv:2512.13616 (2025)].
Derived from the Wigner formulation of quantum mechanics, the WTE describes heat transport in terms of particlelike and wavelike conduction mechanisms. The full and very detailed derivation can be found in the work by Simoncelli, Marzari and Mauri in their paper “Wigner Formulation of Thermal Transport in Solids” [Phys. Rev. X 12 (2022)].