Improved bounds on some entanglement criteria in bipartite quantum systems.

Entanglement detection is one of the core tasks in quantum information processing. Based on a broad class of informationally complete symmetric measurements, a series of separability criteria are proposed for different bipartite quantum systems using Cauchy–Schwarz inequality and ρ − ρ A ⊗ ρ B , respectively. In addition, by comparing and analyzing the existing entanglement criteria and detailed examples, it is not difficult to prove that our proposed criteria are more powerful and comprehensive in entanglement detection. • Some tighter lower bounds for entanglement criteria have been proposed via (N, M)-POVMs. • The lower bound relations between the proposed criteria have been proved. • Compared with the MUMs or GSIC-POVMs criteria, the proposed criteria are more flexible in physical experiments, since requiring only a few local measurements. [ABSTRACT FROM AUTHOR]