On the fidelity of mixed states of two qubits
Quantum Physics
2009-11-07 v3
Abstract
We consider a single copy of a mixed state of two qubits and show how its fidelity or maximal singlet fraction is related to the entanglement measures concurrence and negativity. We characterize the extreme points of the convex set of states with constant fidelity, and use this to prove tight lower and upper bounds on the fidelity for a given amount of entanglement.
Keywords
Cite
@article{arxiv.quant-ph/0203073,
title = {On the fidelity of mixed states of two qubits},
author = {Frank Verstraete and Henri Verschelde},
journal= {arXiv preprint arXiv:quant-ph/0203073},
year = {2009}
}
Comments
4 pages; part I of quant-ph/0203073v2; see quant-ph/0303007 for part II