English

Two-parameter bipartite entanglement measure

Quantum Physics 2026-02-02 v1

Abstract

Entanglement concurrence is an important bipartite entanglement measure that has found wide applications in quantum technologies. In this work, inspired by unified entropy, we introduce a two-parameter family of entanglement measures, referred to as the unified (q,s)(q,s)-concurrence. Both the standard entanglement concurrence and the recently proposed qq-concurrence emerge as special cases within this family. By combining the positive partial transposition and realignment criteria, we derive an analytical lower bound for this measure for arbitrary bipartite mixed states, revealing a connection to strong separability criteria. Explicit expressions are obtained for the unified (q,s)(q,s)-concurrence in the cases of isotropic and Werner states under the constraint q>1q>1 and qs1qs\geq 1. Furthermore, we explore the monogamy properties of the unified (q,s)(q,s)-concurrence for q2q\geq 2, 0s10\leq s\leq 1 and 1qs31\leq qs\leq 3, in qubit systems. In addition, we derive an entanglement polygon inequality for the unified (q,s)(q,s)-concurrence with q1q\geq 1 and qs1qs\geq 1, which manifests the relationship among all the marginal entanglements in any multipartite qudit system.

Keywords

Cite

@article{arxiv.2601.22568,
  title  = {Two-parameter bipartite entanglement measure},
  author = {Chen-Ming Bai and Yu Luo},
  journal= {arXiv preprint arXiv:2601.22568},
  year   = {2026}
}

Comments

28 pages, 6 figures

R2 v1 2026-07-01T09:27:08.431Z