More Communication with Less Entanglement

TL;DR

This paper demonstrates that in quantum communication, less entanglement can sometimes be more effective, revealing conditions under which resource states optimize protocols like teleportation and superdense coding.

Contribution

It introduces a condition based on von-Neumann entropy for resource states to efficiently perform quantum communication tasks.

Findings

Less entanglement can enhance quantum communication efficiency.

A specific entropy condition determines resource state suitability.

Some states are optimal for superdense coding but not for teleportation.

Abstract

We exhibit the intriguing phenomena of "Less is More" using a set of multipartite entangled states. We consider the quantum communication protocols for the {\em exact} teleportation, superdense coding, and quantum key distribution. We find that sometimes {\em less} entanglement is {\em more} useful. To understand this phenomena we obtain a condition that a resource state must satisfy to communicate a $n$-qubit pure state with $m$ terms. We find that the an appropriate partition of the resource state should have a von-Neumann entropy of ${\rm log}_{2} m$. Furthermore, it is shown that some states may be suitable for exact superdense coding, but not for exact teleportation.