In recent decades, a great variety of researches and applications concerning Bell nonlocality have been developed with the advent of quantum information science. Providing that Bell nonlocality can be revealed by the violation of a family of Bell inequalities, finding maximal Bell violation (MBV) for unknown quantum states becomes an important and inevitable task during Bell experiments. In this paper we introduce a self-guide method to find MBVs for unknown states using a stochastic gradient ascent algorithm (SGA), by parameterizing the corresponding Bell operators. For all the investigated systems (2-qubit, 3-qubit and 2-qutrit), this method can ascertain the MBV accurately within 100 iterations. Moreover, SGA exhibits significant superiority in efficiency, robustness and versatility compared to other possible methods.
Cite
@article{arxiv.1707.05449,
title = {A self-guide method to search maximal Bell violation for unknown quantum states},
author = {Li-Kai Yang and Geng Chen and Wen-Hao Zhang and Xi-Xiang Peng and Shang Yu and Chuan-Feng Li and Guang-Can Guo},
journal= {arXiv preprint arXiv:1707.05449},
year = {2017}
}