X-matrices provide a lower bound of concurrence
Quantum Physics
2012-04-19 v1
Abstract
By focusing on the X-matrix part of a density matrix of two qubits we provide an algebraic lower bound for the concurrence. The lower bound is generalized for cases beyond two qubits and can serve as a sufficient condition for non-separability for bipartite density matrices of arbitrary dimension. Experimentally, our lower bound can be used to confirm non-separability without performing a complete state tomography.
Cite
@article{arxiv.1204.3912,
title = {X-matrices provide a lower bound of concurrence},
author = {S. M. Hashemi rafsanjani and S. Agarwal},
journal= {arXiv preprint arXiv:1204.3912},
year = {2012}
}