Quantum secret sharing in tripartite superconducting network
W. K. Yam, C. Wilkinson, S. Gandorfer, F. Fesquet, M. Handschuh, A. Marx, R. Gross, N. Korolkova
Abstract
Superconducting microwave quantum networks is a rapidly developing field, enabling distributed quantum computing and holding a promise for hybrid architectures in quantum internet. Quantum secret sharing (QSS) is one of the key protocols for multipartite quantum networks and can provide an unconditionally secure way to share quantum states among players. Using microwave two-mode squeezed states as an entanglement resource, we experimentally implement a QSS protocol with , where a subset of at least players must collaborate to faithfully reconstruct the original secret state. We demonstrate reconstructed-state fidelities that surpass the asymptotic no-cloning threshold of and identify a parameter regime that allows for unconditionally secure communication in the presence of an omnipotent dishonest player. Furthermore, we experimentally explore inherent connections between QSS and other important quantum information processing tasks, such as quantum dense coding and elementary quantum error correction of channel erasures. Finally, we discuss extensions of QSS and its relation to the concept of blind quantum computing.
AI Impact Assessments
(3 models)Scientific Impact Assessment
1. Core Contribution
This paper presents the first experimental demonstration of a continuous-variable (CV) quantum secret sharing (QSS) protocol in the microwave frequency regime, implemented using a tripartite superconducting network. The ((2,3)) threshold scheme distributes a secret coherent state among three players, requiring at least two to collaborate for reconstruction. The key novelty is translating QSS — previously demonstrated only in optical platforms — into the superconducting microwave domain at ~5.4 GHz, leveraging Josephson parametric amplifiers (JPAs) for both entanglement generation and state reconstruction. Beyond the core QSS demonstration, the authors reinterpret the same experimental framework for quantum dense coding and erasure error correction, positioning QSS as a versatile primitive ("Swiss Army knife") for microwave quantum networks.
2. Methodological Rigor
The experimental methodology is sound and well-structured. The authors employ established superconducting circuit techniques: flux-driven JPAs for two-mode squeezed (TMS) state generation, microwave hybrid rings for beam splitter operations, and Planck spectroscopy for calibration. Quantum state tomography via statistical moments up to fourth order (with ~10⁸ averages) provides reliable Gaussian state characterization.
The security analysis is conducted at two levels: (i) mutual information comparison assuming trusted channels, and (ii) no-cloning fidelity thresholds for unconditional security against omnipotent adversaries. This two-tiered approach is thorough. The authors demonstrate fidelities exceeding the asymptotic no-cloning threshold F_nc = 2/3 and identify a specific codebook variance range (1.92 ≤ σ² ≤ 3.81) where unconditional security holds, with a maximum excess fidelity δ = 0.0073 above the codebook-specific threshold. While this margin is small, it is clearly resolved experimentally.
The theory model based on beam splitter formalism fits the experimental data well across multiple parameter regimes. The characterization of TMS resource quality (negativity and purity vs. squeezing level) and the identification of optimal operating points (S = 6 dB, G = 7 dB) demonstrate careful experimental optimization. One limitation is that systematic effects — particularly higher-order JPA nonlinearities and phase mismatches between hybrid rings — are acknowledged but not fully mitigated, limiting performance at higher squeezing levels and larger displacements.
3. Potential Impact
Superconducting quantum networks: This work contributes to the growing portfolio of quantum communication protocols demonstrated in superconducting microwave systems, following teleportation and entanglement distribution. QSS is particularly relevant for distributed quantum computing architectures where multiple superconducting processors must securely share quantum information.
Hybrid quantum internet: The authors position their work within a vision of hybrid microwave-optical quantum networks. While the current implementation is local (cryogenic), it establishes protocol-level compatibility that could integrate with microwave-to-optical transduction for longer-range communication.
Dense coding and error correction: The demonstration that a single experimental platform supports QSS, dense coding (with MI exceeding classical limits), and erasure error correction (up to 2.83% fidelity advantage) highlights the versatility of TMS-based multipartite protocols. The erasure correction capability is particularly relevant for realistic noisy networks.
Blind quantum computing (BQC): The discussion connecting QSS to BQC is speculative but forward-looking. If QSS shares can undergo gate operations without decoding, this could enable privacy-preserving distributed computation on superconducting platforms — a compelling application given that superconducting systems are leading quantum computing platforms.
4. Timeliness & Relevance
The paper addresses a timely need: as superconducting quantum processors scale, distributed architectures requiring secure inter-node communication become essential. The work also responds to recent theoretical advances (Ref. [10], 2023) that generalized CV-QSS to asymmetric Gaussian resources. The convergence of improved JPA fabrication (Ref. [12], 2025) and microwave quantum networking capabilities makes this demonstration well-timed.
The relevance to microwave open-air quantum communication (cited estimates of positive key rates over short distances) adds a speculative but interesting dimension, given recent arguments that microwave CV-QKD may be more robust against weather than optical counterparts.
5. Strengths & Limitations
Strengths:
Limitations:
Additional observations: The paper is well-written with clear figures and logical structure. The connection to multiple protocols from a unified experimental framework is pedagogically valuable. The codebook-dependent security analysis (Eq. 12) adds nuance beyond simple asymptotic thresholds. Reproducibility is supported by the detailed description of experimental parameters, though the complexity of the superconducting setup limits accessibility.
Summary
This is a solid experimental demonstration that extends CV quantum secret sharing to the microwave domain, with meaningful connections to dense coding and error correction. While the margins are thin and the implementation local, it represents a genuine advance for superconducting quantum networks and lays groundwork for more complex multipartite protocols. The impact is primarily within the superconducting quantum communication community, with broader relevance to hybrid quantum network design.
Generated Apr 16, 2026
Comparison History (38)
Paper 1 presents a novel experimental demonstration of a key multipartite protocol (quantum secret sharing) in superconducting microwave networks, surpassing the no-cloning threshold. Experimental milestones in quantum networking generally have broader immediate impact and lay the groundwork for future hybrid quantum internet architectures. While Paper 2 offers a valuable theoretical optimization for fault-tolerant quantum computing overhead, Paper 1's experimental realization and its connections to multiple quantum information tasks provide a wider breadth of impact and foundational advancement.
Paper 1 addresses a fundamental and pressing problem in quantum computing—understanding why gatemon qubits have lower coherence than standard transmons. By co-fabricating both types on the same chip and systematically constructing a loss budget, it definitively identifies junction-intrinsic dissipation as the dominant limitation. This insight directly guides future materials and device engineering for a major qubit platform. Paper 2 demonstrates a QSS protocol in superconducting networks, which is a valuable but more incremental advance in quantum communication protocols. Paper 1's methodological rigor and direct implications for improving qubit performance give it broader and deeper impact.
Paper 2 has higher estimated impact: it experimentally demonstrates a foundational multipartite quantum-network protocol (3-party QSS with a 2-of-3 threshold) in superconducting microwave hardware, surpassing the no-cloning fidelity bound and addressing security against a powerful dishonest player. This is timely for quantum internet/distributed QC, has clear protocol-level real-world applications (secure state sharing), and connects to dense coding and error correction, broadening cross-field relevance. Paper 1 is a valuable technical advance for scaling Rydberg arrays, but is more incremental and narrower in scope (laser/amp engineering for a specific platform).
Paper 2 presents a successful experimental implementation of quantum secret sharing in a superconducting microwave network, surpassing the no-cloning threshold. Its experimental validation of multipartite secure communication directly advances the highly relevant and impactful fields of distributed quantum computing and the quantum internet. While Paper 1 offers valuable theoretical insights into atomic arrays, Paper 2's tangible experimental results and clear real-world applications in secure quantum networks give it a broader and more immediate scientific impact.
Paper 2 presents a scalable computational framework addressing a fundamental bottleneck in simulating many-body quantum transport across large networks (hundreds to thousands of sites). This has broader impact across multiple fields including light-harvesting complexes, disordered semiconductors, and biological energy transport. The methodological innovation of combining variational polaron transformations with efficient partitioning schemes enables previously intractable problems. Paper 1, while a solid experimental demonstration of quantum secret sharing in superconducting networks, represents an incremental advance applying known protocols to a specific platform with modest scale (n=3 players).
Paper 2 presents an experimental realization of quantum secret sharing in a superconducting network, a significant milestone for distributed quantum computing and the quantum internet. Its demonstration of unconditional security and exploration of related quantum tasks offer broader, more immediate real-world applications and impact compared to the theoretical and numerical focus of Paper 1, which focuses on stabilizing specific quantum states.
Paper 1 establishes a novel theoretical connection between fundamental quantum resources (entanglement, magic) and Trotter simulation errors, revealing a paradoxical constructive role of quantum complexity in simulation robustness. This addresses a foundational open question with broad implications for quantum computing theory and algorithm design. Paper 2 demonstrates an important but more incremental experimental implementation of quantum secret sharing in superconducting networks. While valuable, QSS protocols have been demonstrated in other platforms. Paper 1's conceptual insight—linking resource theory to algorithmic performance—opens new research directions across quantum information, simulation, and complexity theory.
Paper 2 has higher potential impact due to a more broadly applicable algorithmic contribution: hybrid quantum-classical methods targeting nonlinear PDEs across multiple equation classes, with claimed exponential scaling improvements in spatial size and extensions to 2D/3D vortex dynamics relevant to superconductivity and beyond. This spans quantum algorithms, numerical analysis, PDEs, and physics, increasing cross-field impact and timeliness in quantum advantage discussions. Paper 1 is a solid experimental advance in superconducting-network QSS, but is narrower (specific protocol, n=3) and likely more incremental relative to the wider reach of Paper 2’s framework.
Paper 1 introduces a broadly applicable theoretical framework: efficient learning of an unknown class of mixed states (trivial-phase) from measurement data, with provable sample/runtime guarantees and explicit generative circuit output. It connects quantum complexity, phases of matter, and quantum machine learning, and even suggests a classical diffusion-model analogue—widening cross-field impact and timeliness. Paper 2 is a strong experimental milestone (tripartite QSS in superconducting networks) with clear relevance to quantum internet, but its scope (n=3) and incremental nature relative to ongoing network demos likely yield narrower long-term impact than Paper 1’s general structural results.
Paper 2 is a comprehensive review/theory paper on spin qubits covering multiple implementations, long-range coupling mechanisms, and scalability pathways. Its breadth across a rapidly advancing field (semiconductor spin qubits) with direct relevance to scalable quantum computing gives it wider impact potential. It serves as a foundational reference for a large community. Paper 1, while experimentally impressive in demonstrating quantum secret sharing in superconducting networks, addresses a more specialized protocol with a narrower scope of impact.
Paper 2 likely has higher scientific impact because it reports an experimental implementation of a core quantum-network cryptographic primitive (3-party QSS) in superconducting microwave hardware, with security-relevant benchmarks (fidelity beyond no-cloning threshold, regime for unconditional security vs dishonest player) and links to dense coding and erasure correction—broadening relevance across quantum communication, networking, and fault tolerance. Paper 1 is a valuable, timely gate-optimization proposal for trapped Rydberg ions with high simulated fidelities and speedups, but its impact is narrower and more contingent on near-term experimental adoption.
Paper 1 likely has higher scientific impact due to strong theoretical novelty and breadth: it gives an optimal (Heisenberg-scaling) certification algorithm for local Hamiltonians, introduces nontrivial tools (hypercontractivity) for Hamiltonian property testing, and provides sample-efficient learning/certification of Gibbs states—addressing a concrete open question. These results are broadly relevant to quantum algorithms, Hamiltonian learning, verification, and quantum simulation. Paper 2 is a valuable experimental milestone in superconducting-network QSS, but it is a smaller-step demonstration (n=3) with more limited cross-field reach compared to Paper 1’s general algorithmic/complexity advances.
Paper 1 demonstrates a fundamental quantum communication protocol (quantum secret sharing) experimentally implemented in superconducting microwave networks—a leading quantum computing platform. It achieves fidelities surpassing no-cloning bounds, demonstrates unconditional security, and connects QSS to dense coding and quantum error correction. This experimental milestone in multipartite quantum networks has broad implications for quantum internet and distributed quantum computing. Paper 2 presents a useful but incremental contribution: a GPU-accelerated simulation framework for quantum molecular generation that remains classical simulation without quantum hardware validation, limiting its near-term impact.
Paper 2 demonstrates experimental implementation of quantum secret sharing in a superconducting network, a key protocol for quantum internet and distributed quantum computing. It achieves fidelities surpassing the no-cloning threshold, demonstrates unconditional security, and connects QSS to dense coding and quantum error correction. Its breadth of impact spans quantum networking, cryptography, and distributed computing. While Paper 1 presents valuable theoretical/computational advances in quantum memory optimization, Paper 2's experimental demonstration in a rapidly growing field with direct applications to quantum internet gives it broader and more timely impact.
Paper 1 has higher likely impact due to an experimental demonstration of quantum secret sharing in a superconducting microwave network, directly advancing quantum-network capabilities with clear relevance to quantum internet and distributed quantum computing. It shows performance beyond a key security/physics threshold (no-cloning), discusses security against a dishonest participant, and connects to dense coding and error correction—broadening cross-field relevance. Paper 2 is methodologically strong and important for open-systems theory, but is more specialized and primarily advances analytic modeling rather than enabling a near-term platform-level protocol demonstration.
Paper 1 presents an experimental demonstration of quantum secret sharing in a superconducting microwave network, achieving fidelities beyond the no-cloning threshold and establishing unconditional security. This represents a significant advance in multipartite quantum networking with superconducting circuits, connecting QSS to dense coding and quantum error correction. Its novelty, experimental rigor, and relevance to quantum internet architectures give it substantially higher impact than Paper 2, which introduces a simulation toolkit—a useful but incremental software contribution with more limited scientific novelty and narrower impact.
Paper 2 likely has higher impact: it reports an experimental implementation of tripartite quantum secret sharing in a superconducting microwave network with fidelities beyond the no-cloning limit and security analysis against a dishonest party. This is timely for quantum networking/quantum internet and broadly relevant across quantum communication, cryptography, and distributed quantum computing, with clear real-world protocol implications. Paper 1 is innovative for bosonic VQD in quantum chemistry and shows promising scaling and gate-count reductions, but is more specialized and appears primarily algorithmic/simulative, with nearer-term impact constrained by availability/maturity of qumode hardware.
Paper 2 presents a significant technical leap by achieving deterministic generation and single-ion-resolved reconstruction of topological spin textures (skyrmions) in a large system of over 150 trapped ions. This scale and level of control provide a powerful new platform for quantum simulation of complex, many-body condensed matter phenomena. While Paper 1 offers a solid demonstration of quantum secret sharing, it is limited to a small 3-node network, making Paper 2's large-scale quantum simulation more broadly impactful across condensed matter and atomic physics.
Paper 2 likely has higher impact due to an experimental demonstration of quantum secret sharing on a superconducting microwave network, directly advancing quantum networking/quantum internet capabilities. It reports fidelities beyond the no-cloning limit and analyzes security against a powerful dishonest player, strengthening real-world relevance. The work also connects QSS to dense coding and erasure correction, broadening cross-field impact. Paper 1 offers valuable circuit-level optimizations (T-count/depth reductions) for a specific arithmetic primitive, but is narrower in scope and primarily architectural/algorithmic rather than a platform-level experimental milestone.
Paper 2 intersects AI-driven discovery with quantum computing, addressing a critical bottleneck in the NISQ era: resource-efficient algorithm design. Its application to quantum chemistry (molecular ground states) represents a highly anticipated real-world use case. While Paper 1 provides a valuable experimental demonstration of quantum secret sharing, Paper 2's automated AI approach to discovering novel, resource-efficient quantum algorithms has broader applicability and transformative potential across multiple domains in quantum computing.