Edge states lying at the edge of positive-partial-transpose- (PPT-) entangled states have a very intriguing existence and their detection is equally interesting. We present here a witness for detection of edge states. We then compare between our proposed witness operator and the witness operator proposed by Lewenstein et al. [Phys. Rev. A 62, 052310 (2000)] in terms of the efficiency in the detection of PPT entangled states. In this regard we show that this operator is finer than the operator of Lewenstein et al. in some restrictions. We also discuss about its experimental realization via Gell-Mann matrices.

• Received 12 June 2009

DOI:https://doi.org/10.1103/PhysRevA.80.032331