A lower bound of concurrence for multipartite quantum systems

TL;DR

This paper introduces a new lower bound for concurrence in four-partite quantum systems, improving entanglement detection and generalizing to larger multipartite systems.

Contribution

It provides an analytical lower bound for four-partite mixed states based on smaller subsystems, enhancing entanglement detection methods.

Findings

Lower bounds outperform existing bounds in entanglement detection

Analytical bounds for 2x2x2x2 mixed states are derived

Method generalizes to larger multipartite quantum systems

Abstract

We present a lower bound of concurrence for four-partite systems in terms of the concurrence for $M\, (2\leq M\leq 3)$ part quantum systems and give an analytical lower bound for $2\otimes2\otimes2\otimes2$ mixed quantum sates. It is shown that these lower bounds are able to improve the existing bounds and detect entanglement better. Furthermore, our approach can be generalized to multipartite quantum systems.