On the dynamics of polarons in the strong-coupling limit

Abstract

The polaron model of H. Fr\"ohlich describes an electron coupled to the quantized longitudinal optical modes of a polar crystal. In the strong-coupling limit one expects that the phonon modes may be treated classically, which leads to a coupled Schr\"odinger-Poisson system with memory. For the effective dynamics of the electron this amounts to a nonlinear and non-local Schr\"odinger equation. We use the Dirac-Frenkel variational principle to derive the Schr\"odinger-Poisson system from the Fr\"ohlich model and we present new results on the accuracy of their solutions for describing the motion of Fr\"ohlich polarons in the strong-coupling limit. Our main result extends to $N$-polaron systems.