Estimating Concurrence via Entanglement Witnesses

Jacek Jurkowski, Dariusz Chruscinski

Published 2010-01-28, updated 2010-02-18Version 2

We show that each entanglement witness detecting given bipartite entangled state provides an estimation of its concurrence. We illustrate our result with several well known examples of entanglement witnesses and compare the corresponding estimation of concurrence with other estimations provided by the trace norm of partial transposition and realignment.