Taming multiparticle entanglement

TL;DR

This paper introduces a new, computationally efficient method for detecting and quantifying genuine multiparticle entanglement, significantly improving upon existing techniques and applicable even with limited experimental data.

Contribution

It develops a semidefinite programming-based criterion for multiparticle entanglement that is more accurate and easier to compute than previous methods, including an analytical approach for cluster states.

Findings

Improves entanglement detection accuracy over existing methods

Enables evaluation with limited observable measurements

Provides an exponential enhancement for cluster state analysis

Abstract

We present an approach to characterize genuine multiparticle entanglement using appropriate approximations in the space of quantum states. This leads to a criterion for entanglement which can easily be calculated using semidefinite programming and improves all existing approaches significantly. Experimentally, it can also be evaluated when only some observables are measured. Furthermore, it results in a computable entanglement monotone for genuine multiparticle entanglement. Based on this, we develop an analytical approach for the entanglement detection in cluster states, leading to an exponential improvement compared with existing schemes.