Experimental high-dimensional quantum secret sharing with spin-orbit-structured photons

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.

Experimental Demonstration of 11‐Dimensional 10‐Party Quantum Secret Sharing

“…[ 25 ] In the context of QSS, high‐dimensional single photon secret sharing has only been demonstrated with at most three dimensions using spatial modes of light. [ 26,27 ]…”

Differential phase shift quantum secret sharing using a twin field

“…Nevertheless, difficulties in preparing and transmitting GHZ states constrains the secret key rate and stability of QSS systems, making it far from practical implementation. Therefore, several protocols in the prepare-and-measure scenario were proposed to circumvent preparations of multipartite entangled states, such as protocols using post-selected multipartite entanglement state [15], Bell states [16,17], continuous variable [18,19], single-qubit scheme [20][21][22][23], d-level scheme [24,25] and differential phase shift scheme [26]. Unfortunately, a majority of prepare-and-measure protocols [20][21][22][23][24][25][26] is vulnerable to the Trojan horse attacks [27,28].…”

Structured Light in Turbulence

“…The idea has been around since the 1980s in fibre and gained momentum in the past 10 years after seminal MDM demonstrations [10][11][12], inspired by work of the Nakazawa group. In free-space the development followed advances in orbital angular momentum (OAM), one of which was a proof-of-principle demonstration of communication down a corridor in the University of Glasgow [13], with many seminal demonstrations quickly following [14][15][16] including interesting applications such as communications to aerial platforms [17], and later with other mode sets [18][19][20][21][22][23][24], as well as with quantum states in the spatial mode basis [25][26][27][28][29][30][31][32][33][34].…”