On estimating the output entropy of a tensor product of the quantum phase-damping channel with an arbitrary channel

TL;DR

This paper provides a lower bound estimate for the output entropy of a tensor product involving the quantum phase-damping channel, demonstrating strong superadditivity for this and related channels.

Contribution

It introduces a new lower bound estimate for the output entropy of tensor products with the quantum phase-damping channel, establishing superadditivity results.

Findings

Strong superadditivity holds for the quantum phase-damping channel

The estimation applies to tensor products with arbitrary channels

Results extend to the quantum depolarizing channel

Abstract

We obtained the estimation from below for the output entropy of a tensor product of the quantum phase-damping channel with an arbitrary channel. It is shown that from this estimation immediately follows that the strong superadditivity of the output entropy holds for this channel as well as for the quantum depolarizing channel.