Extraction of Pure Entangled States from Many Body Systems by Distant Local Projections

TL;DR

This paper demonstrates that pure entangled states can be extracted from distant regions of quantum many-body systems using local measurements, applicable in both ground and non-equilibrium states, with a general optimal extraction procedure.

Contribution

It introduces a general method for optimal extraction of pure entangled states via local projections in many-body systems, linking it to the system's quantum numbers.

Findings

Pure entangled states can be extracted in non-equilibrium and ground states.

Local measurements like magnetization enable entanglement extraction.

Extraction efficiency relates to the Hamiltonian's quantum numbers.

Abstract

We study the feasibility of extracting a pure entangled state of non-complementary, and potentially well separated, regions of a quantum many-body system. It is shown that this can indeed be accomplished in non-equilibrium scenarios as well as the ground state of the considered spin chain models when one locally measures observables such as magnetization in separated blocks of spins. A general procedure is presented, which can search for the optimal way to extract a pure entangled state through local projections. Our results indicate a connection of the projective extraction of entanglement to good quantum numbers of the underlying Hamiltonian.