Validity of the Franck-Condon principle in the optical spectroscopy: optical conductivity of the Fröhlich polaron.

  title={Validity of the Franck-Condon principle in the optical spectroscopy: optical conductivity of the Fr{\"o}hlich polaron.},
  author={Giulio De Filippis and Vittorio Cataudella and Andrei S. Mishchenko and Carmine Antonio Perroni and Jozef T. Devreese},
  journal={Physical review letters},
  volume={96 13},
The optical absorption of the Fröhlich polaron model is obtained by an approximation-free diagrammatic Monte Carlo method and compared with two new approximate approaches that treat lattice relaxation effects in different ways. We show that: (i) a strong coupling expansion, based on the Franck-Condon principle, well describes the optical conductivity for large coupling strengths (alpha > 10); (ii) a memory function formalism with phonon broadened levels reproduces the optical response for weak… Expand

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