A Path Integral Ground State Monte Carlo Algorithm for Entanglement of Lattice Bosons

TL;DR

This paper introduces a ground state path integral quantum Monte Carlo algorithm to study entanglement in lattice bosons, enabling analysis of large systems and confirming entanglement boundary laws at critical points.

Contribution

The paper presents a novel Monte Carlo algorithm for entanglement measurement in lattice bosons at zero temperature, extending capabilities beyond exact diagonalization.

Findings

Successfully computed Re9nyi entanglement entropy for large 1D systems.

Confirmed entanglement boundary law at the 2D superfluid-insulator critical point.

Extended the estimator to measure symmetry-resolved entanglement.

Abstract

A ground state path integral quantum Monte Carlo algorithm is introduced that allows for the study of entanglement in lattice bosons at zero temperature. The R\'enyi entanglement entropy between spatial subregions is explored across the phase diagram of the one dimensional Bose-Hubbard model for systems consisting of up to $L=256$ sites at unit-filling without any restrictions on site occupancy, far beyond the reach of exact diagonalization. The favorable scaling of the algorithm is demonstrated through a further measurement of the R\'enyi entanglement entropy at the two dimensional superfluid-insulator critical point for large system sizes, confirming the existence of the expected entanglement boundary law in the ground state. The R\'enyi estimator is extended to measure the symmetry resolved entanglement that is operationally accessible as a resource for experimentally relevant lattice gases with fixed total particle number.