Memory effects in quantum information transmission across a Hamiltonian dephasing channel

Abstract

We study a dephasing channel with memory, modelled by a multimode environment of oscillators. Focusing on the case of two channel uses, we show that memory effects can enhance the amount of coherent quantum information transmitted down the channel. We also show the Kraus representation for two channel uses. Finally, we propose a coding-decoding scheme that takes advantage of memory to improve the fidelity of transmission.