The Bose-Hubbard polaron from weak to strong coupling
arXiv:2508.00486 · doi:10.1103/vx5s-cx17
Abstract
We investigate the zero-temperature properties of a mobile impurity immersed in a bath of bosonic particles confined to a square lattice. We analyze the regimes of attractive and repulsive coupling between the impurity and the bath particles for different strengths of boson-boson interactions in the bath, using exact large-scale quantum Monte-Carlo simulations in the grand canonical ensemble. For weak coupling, the polaron mass ratio is found to decrease around the Mott insulator (MI) to superfluid (SF) transition of the bath, as predicted by recent theory, confirming the possible use of the impurity as a probe for the transition. For strong coupling in the MI regime, instead, the impurity is found to modify the bath density by binding to an extra bath particle or a hole, depending on the sign of the polaron-bath interactions. While the binding prevent the aforementioned use of the polaron mass ratio as an MI-SF transition probe, we show that it can be used instead as a probe of the binding itself. Our exact numerical results provide a benchmark for comparing lattice Bose polaron theories and are relevant for experiments with cold atoms trapped in optical lattices, where the presence of a confining harmonic potential can be modeled by a slowly varying local chemical potential.
References in corpus (12)
- Monte Carlo study of two-dimensional Bose-Hubbard model
- Two-particle states in the Hubbard model
- Quantum Monte-Carlo study of the Bose polaron problem in a one-dimensional gas with contact interactions
- Bragg spectroscopy of trapped one dimensional strongly interacting bosons in optical lattices: Probing the cake-structure
- Lattice polarons across the superfluid to Mott insulator transition
- Canonical Trajectories and Critical Coupling of the Bose-Hubbard Hamiltonian in a Harmonic Trap
- Superfluid and Mott Insulating shells of bosons in harmonically confined optical lattices
- Polarons and bipolarons in a two-dimensional square lattice
- Controlling the interactions in a cold atom quantum impurity system
- Bound impurities in a one-dimensional Bose lattice gas: low-energy properties and quench-induced dynamics
- Polaron spectra and edge singularities for correlated flat bands
- Lattice Bose polarons at strong coupling and quantum criticality