Experimental quantum secret sharing with spin-orbit structured photons
This work provides a practical, scalable method for secure information sharing across multiple parties, which is incremental but crucial for advancing quantum networks.
The researchers tackled the problem of securely sharing secret information among multiple parties by developing a quantum secret sharing protocol using spin-orbit structured photons, achieving up to 10 participants in 2D and 3 participants in 3D with image reconstruction fidelity up to 0.979.
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.