Quantum secure direct communication with SU(2) invariant separable polarisation- OAM states

TL;DR

This paper introduces a quantum secure direct communication protocol utilizing SU(2)-invariant separable states, which are experimentally realizable as incoherent superpositions of polarisation-OAM states, offering a new approach to quantum communication.

Contribution

The paper presents a novel protocol based on SU(2)-invariant separable states, expanding quantum communication methods beyond entangled states.

Findings

Protocol leverages SU(2)-invariant separable states

States are experimentally realizable as incoherent superpositions

Potential for secure quantum communication without entanglement

Abstract

We propose a quantum secure direct communication protocol using SU (2)- invariant $2\times N$ separable states, identified as separable equivalents of two-qubit entangled Werner states in [Bharath & Ravishankar, Phys. Rev. A 89, 062110}]. These states can be experimentally realized as incoherent superpositions of separable polarisation-OAM states.