Experimental quantum secret sharing with spin-orbit structured photons

TL;DR

This paper demonstrates a scalable quantum secret sharing protocol using spin-orbit structured photons, achieving high fidelity secret reconstruction with up to ten participants and three-dimensional encoding.

Contribution

It introduces a high-dimensional, multi-party quantum secret sharing scheme utilizing hybrid spin and orbital angular momentum states with linear optics.

Findings

Achieved secret sharing with up to ten participants in two dimensions.

Demonstrated three-dimensional secret sharing with three participants.

Reconstructed secrets with fidelity up to 0.979.

Abstract

Secret sharing allows three or more parties to share secret information which can only be decrypted through collaboration. It complements quantum key distribution as a valuable resource for securely distributing information. Here we take advantage of hybrid spin and orbital angular momentum states to access a high dimensional encoding space, demonstrating a protocol that is easily scalable in both dimension and participants. To illustrate the versatility of our approach, we first demonstrate the protocol in two dimensions, extending the number of participants to ten, and then demonstrate the protocol in three dimensions with three participants, the highest realisation of participants and dimensions thus far. We reconstruct secrets depicted as images with a fidelity of up to 0.979. Moreover, our scheme exploits the use of conventional linear optics to emulate the quantum gates needed for transitions between basis modes on a high dimensional Hilbert space with the potential of up to 1.225 bits of encoding capacity per transmitted photon. Our work offers a practical approach for sharing information across multiple parties, a crucial element of any quantum network.