Study of one-dimensional Holstein polaron in infinite lattice
有限格点一维Holstein极化子研究

Applying the method of coherent state orthogonal expansion, an analytical expression of the ground state energy for one-dimensional Holstein model is obtained. We expand the trial wave function of ground state to third order, and calculate the ground state energy for different lattice sites and different coupling intensities. In the third order approximation, the ground state energy agrees with the numerical solution.