Beyond the Goldenberg-Vaidman protocol: Secure and efficient quantum communication using arbitrary, orthogonal, multi-particle quantum states

TL;DR

This paper demonstrates that secure direct quantum communication protocols can be constructed using any orthogonal multi-particle quantum states, broadening the options beyond traditional states like GHZ or W states, and establishing their security based on entanglement properties.

Contribution

It introduces a generalized framework for secure quantum communication using arbitrary orthogonal states, extending the Goldenberg-Vaidman protocol and analyzing security from entanglement principles.

Findings

Any orthogonal basis can be used for maximally efficient secure communication.

No particular quantum state set has an inherent advantage over others, aside from implementation difficulty.

Security relies on entanglement duality and monogamy, not non-orthogonality.

Abstract

It is shown that maximally efficient protocols for secure direct quantum communications can be constructed using any arbitrary orthogonal basis. This establishes that no set of quantum states (e.g. GHZ states, W states, Brown states or Cluster states) has an advantage over the others, barring the relative difficulty in physical implementation. The work provides a wide choice of states for experimental realization of direct secure quantum communication protocols. We have also shown that this protocol can be generalized to a completely orthogonal state based protocol of Goldenberg-Vaidman (GV) type. The security of these protocols essentially arises from duality and monogamy of entanglement. This stands in contrast to protocols that employ non-orthogonal states, like Bennett-Brassard 1984 (BB84), where the security essentially comes from non-commutativity in the observable algebra.