Optimal convex approximations of quantum states
Quantum Physics
2019-01-24 v2
Abstract
We consider the problem of optimally approximating an unavailable quantum state by the convex mixing of states drawn from a set of available states . The problem is recast to look for the least distinguishable state from among the convex set , and the corresponding optimal weights provide the optimal convex mixing. We present the complete solution for the optimal convex approximation of a qubit mixed state when the set of available states comprises the three bases of the Pauli matrices.
Cite
@article{arxiv.1710.01565,
title = {Optimal convex approximations of quantum states},
author = {Massimiliano F. Sacchi},
journal= {arXiv preprint arXiv:1710.01565},
year = {2019}
}
Comments
5 pages; 2 figures; added the section 'Addendum' and a reference to X.-B. Liang, B. Li, and S.-M. Fei, Phys. Rev. A 99, 016301 (2019), which corrects some results of Sec. III