Comment on path-integral treatment of the large-bipolaron problem

Abstract

We show that the recent path-integral calculation of Khandekar et al. [Phys. Rev. B 43, 9750 (1991)] for the ground-state energy of a large optical bipolaron neglects the Coulomb correlation effects completely and therefore leads to an incorrect stability condition. We furthermore show that their calculation for the bipolaron effective mass also leads to erroneous results. © 1992 The American Physical Society.