For quantum information, two wrongs can make a right

TL;DR

This paper explains the superactivation phenomenon in quantum information, where combining two zero-capacity channels results in a positive capacity, and provides a protocol to activate private channels.

Contribution

It offers an intuitive explanation for superactivation and introduces a protocol to activate any private quantum channel.

Findings

Superactivation allows zero-capacity channels to achieve positive capacity when combined.

A protocol is proposed to activate private quantum channels.

The paper provides an intuitive understanding of superactivation in quantum information.

Abstract

Superactivation is the phenomenon where two quantum channels which individually have zero-capacity can have positive capacity when used together. The perspective given here provides an intuitive explanation of this discovery by Smith and Yard, and gives a protocol to activate any private channel.