Memory effects in quantum information transmission across a Hamiltonian dephasing channel

TL;DR

This paper investigates how memory effects in a quantum dephasing channel can enhance quantum information transmission, providing a Kraus representation and a coding scheme that leverages memory for improved fidelity.

Contribution

It introduces a model of a dephasing channel with memory, derives its Kraus representation for two uses, and proposes a coding scheme that exploits memory effects to boost transmission fidelity.

Findings

Memory effects can increase coherent quantum information transmission.

A Kraus representation for two channel uses is derived.

A coding-decoding scheme utilizing memory improves fidelity.

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.