Coherent control of multipartite entanglement

TL;DR

This paper presents a method for deterministic, non-probabilistic control of multipartite entanglement in quantum systems, enabling management of entanglement dynamics in multi-qubit states using external controls.

Contribution

It introduces a novel approach to manage entanglement in multi-qubit systems, including the permanent death of all-party entanglement for four or more qubits and indefinite control of weak inseparability.

Findings

All-party entanglement permanently dies after initial collapse for N≥4.

Weak inseparability can be maintained almost indefinitely for large N.

External control mechanisms can deterministically manage entanglement dynamics.

Abstract

Quantum entanglement between an arbitrary number of remote qubits is examined analytically. We show that there is a non-probabilistic way to address in one context the management of entanglement of an arbitrary number of mixed-state qubits by engaging quantitative measures of entanglement and a specific external control mechanism. Both all-party entanglement and weak inseparability are considered. We show that for $N\ge4$, the death of all-party entanglement is permanent after an initial collapse. In contrast, weak inseparability can be deterministically managed for an arbitrarily large number of qubits almost indefinitely. Our result suggests a picture of the path that the system traverses in the Hilbert space.