A ground-state path-integrated quantum Monte Carlo algorithm is introduced that allows the study of lattice boson entanglement at zero temperature. The R\’enyi entanglement entropy between spatial subregions is explored across the phase diagram of his one-dimensional Bose-Hubbard model for systems consisting of up to L = 256 sites with unit packing, without site occupancy restrictions. will be Reaching exact diagonalization. Proper scaling of the algorithm is demonstrated by further measurements of the R\’enyi entanglement entropy at the critical point of a two-dimensional superfluid insulator for large system sizes, confirming the existence of the expected entanglement boundary law in the ground state. Confirmed. The R\’enyi estimator is extended to measure symmetry-resolved entanglements, operationally accessible as a resource of experimentally relevant lattice gases with a fixed total particle number.
