Polarons and bipolarons in Rydberg-dressed extended Bose-Hubbard model

Abstract: Impurities immersed in hard-core Bose gases offer exciting opportunities to explore polaron and bipolaron physics. We investigate the ground state properties of a single and a pair of impurities throughout the superfluid and insulating (charge density wave) phases of the bosonic environment. In the superfluid phase, we demonstrate that the impurity undergoes a polaron-like transition, shifting from behaving as an individual particle to becoming a dressed quasiparticle as the coupling with the bath increases. However, in the insulating phase, the impurity can maintain its individual character, moving through a potential landscape shaped by the charge density wave order. Moreover, we show that two impurities can form a bound state even in the absence of an explicit impurity-impurity coupling. Furthermore, we establish the stability of this bound state within both the superfluid and insulating phases. Our results offer valuable insights for ongoing lattice polaron experiments with ultracold gases.