Highly efficient estimation of entanglement measures for large experimentally created graph states via simple measurements
Abstract
Quantifying experimentally created entanglement could in principle be accomplished by measuring the entire density matrix and calculating an entanglement measure of choice thereafter. Due to the tensor structure of the Hilbert space, this approach becomes unfeasible even for mediumsized systems. Here we present methods for quantifying the entanglement of arbitrarily large twocolorable graph states from simple measurements. The presented methods provide nontrivial bounds on the entanglement for any state as long as there is sufficient fidelity with such a graph state. The measurement data considered here is merely given by stabilizer measurements, thus leading to an exponential reduction in the number of measurements required. We provide analytical results for the robustness of entanglement and the relative entropy of entanglement.
 Publication:

New Journal of Physics
 Pub Date:
 August 2010
 DOI:
 10.1088/13672630/12/8/083026
 arXiv:
 arXiv:1003.1681
 Bibcode:
 2010NJPh...12h3026W
 Keywords:

 Quantum Physics
 EPrint:
 New J. Phys. 12, 083026 (2010)