Physics – Quantum Physics
Scientific paper
2009-07-28
Optics Communications 283, 805-813 (2010)
Physics
Quantum Physics
12 pages, 2 figures, revised version due to the partial overlap with results of arXiv:0704.3348, some new results on extremali
Scientific paper
We study extremality in various sets of states that have positive partial transposes. One of the tools we use for this purpose is the recently formulated criterion allowing to judge if a given state is extremal in the set of PPT states. First we investigate qubit--ququart states and show that the only candidates for extremal PPT entangled states (PPTES) have ranks of the state and its partial transposition (5,5) or (5,6) (equivalently (6,5)). Then, examples of extremal states of (5,5) type and the so--called edge states of type (5,6) are provided. We also make an attempt to explore the set of PPT states with ranks (5,6). Finally, we discuss what are the possible configurations of ranks of density matrices and their respective partial transposition in general three-qubit and four-qubit symmetric states for which there may exist extremal entangled PPT states. For instance in the first case we show that the only possibilities are (4,4,4) and (4,4,5).
Augusiak Remigiusz
Grabowski Janusz
Kus Marek
Lewenstein Maciej
No associations
LandOfFree
Searching for extremal PPT entangled states does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Searching for extremal PPT entangled states, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Searching for extremal PPT entangled states will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-682468