Mobile Bipolaron—Strong Coupling Approach

Abstract

We explore the properties of the bipolaron in a 1D Holstein-Hubbard model with dynamical quantum phonons. We apply strong coupling theory to investigate the intersite bipolaron. We investigate the influence of the Hubbard interaction on the bipolaron binding energy, effective mass, and phase diagram. We compare our analytic results to recent numerical calculations [1]. In the intermediate and strong coupling regimes, a bipolaron is stable beyond the naive stability limit U 0 = 2ωg 2 . The intersite bipolaron has a significantly reduced mass compared to the single site bipolaron, and is stable in the strong coupling regime up to U c ∼ 4ωg 2 .