Enhancing phase-covariant channel performance with non-unitality
Quantum Physics
2023-05-03 v1 Mathematical Physics
math.MP
Abstract
We analyze quantum communication properties of phase-covariant channels depending on their degree of non-unitality. In particular, we derive analytical formulas for minimal and maximal channel fidelity on pure states and maximal output purity. Next, we introduce a measure of non-unitality and show how to manipulate between unital and maximally non-unital maps by considering classical mixtures of quantum channels. Finally, we prove that maximal fidelity and maximal output purity increase with non-unitality and present several examples. Interestingly, non-unitality can also prolong quantum entanglement and lead to its rebirth.
Keywords
Cite
@article{arxiv.2212.04876,
title = {Enhancing phase-covariant channel performance with non-unitality},
author = {Katarzyna Siudzińska and Michał Studziński},
journal= {arXiv preprint arXiv:2212.04876},
year = {2023}
}