We present an iterative algorithm that finds the optimal measurement for extracting the accessible information in any quantum communication scenario. The maximization is achieved by a steepest-ascent approach toward the extremal point, following the gradient uphill in sufficiently small steps. We apply it to a simple ad-hoc example, as well as to a problem with a bearing on the security of a tomographic protocol for quantum key distribution.
@article{arxiv.quant-ph/0408134,
title = {Iterative procedure for computing accessible information in quantum communication},
author = {Jaroslav Řeháček and Berthold-Georg Englert and Dagomir Kaszlikowski},
journal= {arXiv preprint arXiv:quant-ph/0408134},
year = {2016}
}