We revise a previous result about the Fröhlich dynamics in the strong coupling limit obtained in Griesemer (Rev Math Phys 29(10):1750030, 2017). In the latter it was shown that the Fröhlich time evolution applied to the initial state varphi _0 otimes xi _alpha , where varphi _0 is the electron ground state of the Pekar energy functional and xi _alpha the associated coherent state of the phonons, can be approximated by a global phase for times small compared to alpha ^2. In the present note we prove that a similar approximation holds for t=O(alpha ^2) if one includes a nontrivial effective dynamics for the phonons that is generated by an operator proportional to alpha ^{-2} and quadratic in creation and annihilation operators. Our result implies that the electron ground state remains close to its initial state for times of order alpha ^2, while the phonon fluctuations around the coherent state xi _alpha can be described by a time-dependent Bogoliubov transformation.
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