Lower Bound of Concurrence for Qubit Systems

Xue-Na Zhu and Shao-Ming Fei

Contact the author: Please use for correspondence this email.
Submission date: 10. Feb. 2014
Pages: 12
published in: Quantum information processing, 13 (2014) 3, p. 815-823 
DOI number (of the published article): 10.1007/s11128-013-0693-7
Bibtex
PACS-Numbers: 03.67.-a, 02.20.Hj, 03.65.-w
Download full preprint: PDF (163 kB)

Abstract:
We study the concurrence of four-qubit quantum states and provide analytical lower bounds of concurrence in terms of the monogamy inequality of concurrence for qubit systems. It is shown that these lower bounds are able to improve the existing bounds and detect entanglement better. The approach is generalized to arbitrary qubit systems.