  EPIq (Electron-Phonon wannier Interpolation over k and q-points) is an
open-source software for the calculation of electron-phonon interaction related
properties from first principles.Acting as a post-processing tool for a
density-functional perturbation theory code ( Quantum ESPRESSO ) and wannier90,
EPIq exploits the localization of the deformation potential in the Wannier
function basis and the stationary properties of a force-constant functional
with respect to the first-order perturbation of the electronic charge density
to calculate many electron-phonon related properties with high accuracy and
free from convergence issues related to Brillouin zone sampling. EPIq features
includes: the adiabatic and non-adiabatic phonon dispersion, superconducting
properties (including the superconducting band gap in the Migdal-Eliashberg
formulation), double-resonant Raman spectra and lifetime of excited carriers.
The possibility to customize most of its input makes EPIq a versatile and
interoperable tool. Particularly relevant is the interaction with the
Stochastic Self-Consistent Harmonic Approximation (SSCHA) allowing anharmonic
effects to be included in the calculation of electron-properties. The
scalability offered by the Wannier representation combined with a
straightforward workflow and easy-to-read input and output files make EPIq
accessible to the wide condensed matter and material science communities.
