We propose an entanglement criterion based on local uncertainty relations (LURs) in a stronger form than the original LUR criterion introduced by Hofmann and Takeuchi [H. F. Hofmann and S. Takeuchi, Phys. Rev. A 68, 032103 (2003)]. Using arbitrarily chosen operators $\{{\mathrm{Â}}_k\}$ and $\{{\mathrm{B̂}}_k\}$ of subsystems A and B, the tighter LUR criterion, which may be used not only for discrete variables but also for continuous variables, can detect more entangled states than the original criterion.

• Received 1 September 2009

DOI:https://doi.org/10.1103/PhysRevA.81.012324