The power of symmetric extensions for entanglement detection

Miguel Navascues, Masaki Owari, Martin B. Plenio

Research output: Contribution to journalArticle (Academic Journal)peer-review

39 Citations (Scopus)


In this paper, we present new progress on the study of the symmetric extension criterion for separability. First, we show that a perturbation of order O(1/N) is sufficient and, in general, necessary to destroy the entanglement of any state admitting an N Bose symmetric extension. On the other hand, the minimum amount of local noise necessary to induce separability on states arising from N Bose symmetric extensions with Positive Partial Transpose (PPT) decreases at least as fast as O(1/N^2). From these results, we derive upper bounds on the time and space complexity of the weak membership problem of separability when attacked via algorithms that search for PPT symmetric extensions. Finally, we show how to estimate the error we incur when we approximate the set of separable states by the set of (PPT) N -extendable quantum states in order to compute the maximum average fidelity in pure state estimation problems, the maximal output purity of quantum channels, and the geometric measure of entanglement.
Original languageUndefined/Unknown
JournalPhysical Review A: Atomic, Molecular and Optical Physics
Publication statusPublished - 15 Jun 2009

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