Quantum information causality

TL;DR

This paper introduces the principle of quantum information causality, establishing the fundamental limit on quantum communication based solely on system dimension, independent of prior shared resources, and demonstrates its implications through a new quantum task.

Contribution

It formulates a new principle of quantum information causality and connects it with optimal quantum communication strategies like teleportation and superdense coding.

Findings

Maximum quantum information communication is bounded by system dimension.

A new quantum task is introduced with success probability limited by the principle.

Optimal strategies combine teleportation, superdense coding, and classical input tasks.

Abstract

How much information can a transmitted physical system fundamentally communicate? We introduce the principle of quantum information causality, which states the maximum amount of quantum information that a quantum system can communicate as a function of its dimension, independently of any previously shared quantum physical resources. We present a new quantum information task, whose success probability is upper bounded by the new principle, and show that an optimal strategy to perform it combines the quantum teleportation and superdense coding protocols with a task that has classical inputs.