Phonons at finite temperature*

We present recent developments using the temperature dependent effective potential technique (TDEP) to model strongly non-harmonic materials. The method employs model Hamiltonians that explicitly depend on temperature. I will present applications pertaining to thermal conductivity, inelastic neutron spectra and phase stabilities. In addition, we investigate the non-adiabatic electron-phonon coupling and their influence on phonon spectra, and recent additions to that deal with nuclear quantum effects and efficient stochastic sampling.