Non-Markovian dynamics in two-qubit dephasing channels with an application to superdense coding

摘要

We study the performance of two measures of non-Markovianity in detectingmemory effects in two-qubit dephasing channels. By combining independentMarkovian and non-Markovian noise on the qubits, our results show that thetrace distance measure is able to detect the memory effects when at least oneof the local channels displays non-Markovianity. A measure based on channelcapacity, in turn, becomes non-zero when the global two-qubit dynamics showsmemory effects. We apply these schemes to a well-known superdense codingprotocol and demonstrate an optimal noise configuration to maximize theinformation transmission with independent local noises.