On Entanglement and Separability

TL;DR

This paper introduces a new necessary and sufficient criterion for determining the entanglement of any N-qubit quantum state and proposes a quantum protocol for superluminal communication and teleportation based on entanglement.

Contribution

It develops a novel approach and criterion for entanglement detection and applies it to create a superluminal communication protocol and enhance quantum teleportation.

Findings

New entanglement criterion for N-qubit states

Protocol for superluminal classical communication

Application to superluminal quantum teleportation

Abstract

We present a necessary and sufficient condition to determine the entanglement status of an arbitrary N-qubit quantum state (may be pure or mixed) represented by the density matrix, (Rho)N. We develop a new approach and a new criterion for the problem of deciding entanglement status. Further, we develop as an important application of entanglement a new quantum protocol for superluminal communication of classical information in terms of a desired ordered sequence of classical bits. We then show that this new quantum protocol for superluminal communication of classical information can be used in the quantum teleportation protocol [12] for achieving superluminal quantum teleportation.