We study the performance of two measures of non-Markovianity in detecting memory effects in two-qubit dephasing channels. By combining independent Markovian and non-Markovian noise on the qubits, our results show that the trace distance measure is able to detect the memory effects when at least one of the local channels displays non-Markovianity. A measure based on channel capacity, in turn, becomes non-zero when the global two-qubit dynamics shows memory effects. We apply these schemes to a well-known superdense coding protocol and demonstrate an optimal noise configuration to maximize the information transmission with independent local noises.
@article{arxiv.1509.05307,
title = {Non-Markovian dynamics in two-qubit dephasing channels with an application to superdense coding},
author = {Antti Karlsson and Henri Lyyra and Elsi-Mari Laine and Sabrina Maniscalco and Jyrki Piilo},
journal= {arXiv preprint arXiv:1509.05307},
year = {2016}
}