Polaron dynamics with a multitude of Davydov D2 trial states

Nengji Zhou, Zhongkai Huang, Jiangfeng Zhu, Vladimir Chernyak, Yang Zhao
2015 Journal of Chemical Physics  
We propose an extension to the Davydov D_2 Ansatz in the dynamics study of the Holstein molecular crystal model with diagonal and off-diagonal exciton-phonon coupling using the Dirac-Frenkel time-dependent variational principle. The new trial state by the name of the "multi-D_2 Ansatz" is a linear combination of Davydov D_2 trial states, and its validity is carefully examined by quantifying how faithfully it follows the Schrödinger equation. Considerable improvements in accuracy have been
more » ... trated in comparison with the usual Davydov trial states, i.e., the single D_1 and D_2 Ansätze. With an increase in the number of the Davydov D_2 trial states in the multi-D_2 Ansatz, deviation from the exact Schrödinger dynamics is gradually diminished, leading to a numerically exact solution to the Schrödinger equation.
doi:10.1063/1.4923009 pmid:26156471 fatcat:togc6uolqjewbllbabvclr4ja4