Critical behaviour in the optimal generation of multipartite entanglement

TL;DR

This paper explores the critical behavior in generating multipartite entanglement, specifically Dicke states, revealing a phase transition in the optimal bipartite entanglement source and its implications for quantum foundations.

Contribution

It introduces a novel scheme to produce Dicke states from bipartite entanglement, highlighting a second-order-like transition in the entanglement properties.

Findings

Dicke states can be generated from bipartite sources with controlled information loss.

The optimal bipartite entanglement undergoes a phase transition depending on the target Dicke state.

Asymptotic entanglement properties between individual qubits and the rest are characterized.

Abstract

Two systems whose correlations cannot be classically accounted for display the simplest instance of quantum entanglement. Although this two-party association has caused a revolution in the foundations and uses of quantum mechanics, genuine entanglement among several parties unveils a whole new class of phenomena and applications. In this work we suggest a way to prepare Dicke states from a tunable source of bipartite entanglement to investigate foundational issues. The scheme has the following distinctive features: (i) it relies on controlled information loss and {\it unentangled} measurements; (ii) irrespective of the source entanglement, whenever a Dicke state is produced, it is ideal; (iii) the optimal entanglement of the bipartite source undergoes a second-order-like transition depending on the parameters of the Dicke state to be produced. These properties lead to asymptotic results on the entanglement between any qubit belonging to a Dicke state and the remaining qubits.