Observable estimation of bipartite mixed-state entanglement
School of Physics and Optoelectronic Technology, Dalian University of
Technology, Dalian 116024, P.R. China
Revised: 7 May 2009
Published online: 6 November 2009
An analytic lower bound is presented for bipartite mixed-state entanglement which is obtained from convex roof construction of a variational definition of pure-state negativity. It is shown that this lower bound can be directly measured by one single projection operator or a few local observables in experiments without the requirement of simultaneous multiple copies of states. In particular, we show that the lower bound can serve as an exact entanglement measure for isotropic states.
PACS: 03.65.Ud – Entanglement and quantum nonlocality (e.g. EPR paradox, Bell's inequalities, GHZ states, etc.) / 03.67.Mn – Entanglement measures, witnesses, and other characterizations / 03.65.Ta – Foundations of quantum mechanics; measurement theory
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2009