Small-to-large polaron crossover in one dimension using variational phonon-averaging techniques

The ground-state properties of polarons in a one-dimensional chain is studi ed analytically within the modified Lang-Firsov (MLF) transformation using various phonon-averaging techniques. The object of the work is to examine h ow the analytical approaches may be improved to give rise to the real pictu re of polaronic properties as predicted by extensive numerical studies. The results are compared with those obtained from numerical analyses using the density matrix renormalization group (DMRG) and other variational techniqu es. It is observed that our results agree well with the numerical results p articularly in the low and intermediate range of phonon coupling.