Removing correlations in signals transmitted over a quantum memory channel

TL;DR

This paper proposes practical transformations to reduce correlations in bosonic quantum memory channels, effectively approximating memoryless channels and improving quantum communication reliability.

Contribution

It introduces a family of feasible transformations that partially remove correlations in bosonic memory channels, bridging the gap with ideal memoryless channels.

Findings

Transformations can significantly reduce correlations

Partial removal of correlations improves channel performance

Feasible methods approach ideal memoryless channel behavior

Abstract

We consider a model of bosonic memory channel, which induces correlations among the transmitted signals. The application of suitable unitary transformations at encoding and decoding stages allows the complete removal of correlations, mapping the memory channel into a memoryless one. However, such transformations, being global over an arbitrary large number of bosonic modes, are not realistically implementable. We then introduce a family of efficiently realizable transformations which can be used to partially remove correlations among errors, and we quantify the reduction of the gap with memoryless channels.