Entanglement in a hardcore-boson Hubbard model

TL;DR

This paper analyzes entanglement properties in a hardcore-boson Hubbard chain, deriving an analytic expression for ground state entanglement and examining how thermal and system size effects influence bipartite and multipartite entanglement.

Contribution

It provides the first analytic expression for global entanglement in the ground state of a hardcore boson Hubbard model and explores entanglement behavior at finite temperatures.

Findings

Derivative of global entanglement diverges at quantum critical point

Thermal entanglement decreases to zero at a critical temperature

Multipartite entanglement vanishes as system size increases

Abstract

The entanglement in a Hubbard chain of hardcore bosons is investigated. The analytic expression of the global entanglement in ground state is derived. The divergence of the derivative of the global entanglement shows the quantum criticality of the ground state. For the thermal equilibrium state, the bipartite and the multipartite entanglement are evaluated. The entanglement decreases to zero at a certain temperature. The thermal entanglement is rapidly decreasing with the increase of the number of sites in the lattice. The bipartite thermal entanglement approaches a constant value at a certain number of sites while the multipartite entanglement eventually vanishes.