REVIEW 3 minor
Superconducting microwave network implements quantum secret sharing where any two of three players reconstruct the secret with fidelity above the no-cloning limit.
Reviewed by Pith at T0; open to challenge. T0 means a machine referee read the full paper against a public rubric. the ladder, T0–T4 →
T0 review · grok-4.3
2026-05-10 12:52 UTC pith:4KFNTIDG
load-bearing objection Experimental QSS on superconducting network clears the no-cloning fidelity threshold with supporting security analysis.
Quantum secret sharing in tripartite superconducting network
The pith
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
Core claim
Using microwave two-mode squeezed states as an entanglement resource, we experimentally implement a QSS protocol with n = 3, where a subset of at least k = 2 players must collaborate to faithfully reconstruct the original secret state. We demonstrate reconstructed-state fidelities that surpass the asymptotic no-cloning threshold of F_nc = 2/3 and identify a parameter regime that allows for unconditionally secure communication in the presence of an omnipotent dishonest player.
What carries the argument
Microwave two-mode squeezed states used as the entanglement resource to encode and distribute the secret across the three-party superconducting network for the (3,2) threshold scheme.
Load-bearing premise
The experimental hardware supplies sufficient entanglement and low enough noise to reach the reported fidelities, and the model of the dishonest player accurately represents possible attacks.
What would settle it
A reconstructed-state fidelity measurement at or below 2/3 under the same entanglement and noise conditions, or an explicit successful attack by a modeled dishonest player that prevents faithful reconstruction by the honest subset.
If this is right
- A parameter regime exists in which the protocol remains secure against an omnipotent dishonest player.
- QSS shares operational structure with quantum dense coding, allowing direct translation of resources between the two tasks.
- The same entanglement distribution supports elementary error correction against channel erasures.
- The protocol architecture extends naturally toward blind quantum computing applications.
Where Pith is reading between the lines
- Integration with existing superconducting processors could support distributed quantum algorithms that require secure multi-party state sharing.
- The demonstrated noise tolerance suggests the platform can be scaled to larger player sets while preserving the threshold advantage.
- Combining this microwave QSS with optical links may enable hybrid quantum internet nodes that mix circuit and photonic modalities.
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The paper experimentally realizes a (2,3) quantum secret sharing protocol in a tripartite superconducting microwave network. Microwave two-mode squeezed states serve as the entanglement resource; any two of the three players can reconstruct the secret state with fidelities exceeding the asymptotic no-cloning bound F_nc = 2/3. A parameter regime is identified that permits unconditional security against an omnipotent dishonest player, and connections are drawn to quantum dense coding and elementary quantum error correction of erasures.
Significance. If the reported fidelities and security bounds hold, the work constitutes a concrete experimental milestone for multipartite quantum communication in superconducting hardware. The explicit mapping between QSS, dense coding, and erasure correction, together with the identification of a secure operating regime, supplies practical guidance for scaling microwave quantum networks.
minor comments (3)
- [§3.2] §3.2 and Fig. 3: the caption and text should explicitly state the number of tomographic measurements per reconstructed state and the precise maximum-likelihood estimator used, as these details directly affect the quoted fidelity uncertainties.
- [§4.1] §4.1, Eq. (8): the bound on the dishonest player’s information is derived under a specific noise model; a short paragraph clarifying how the measured squeezing level and channel loss map onto the parameters of that model would strengthen the security claim.
- [Fig. 5] Fig. 5: the color scale for the reconstructed density matrices should be labeled with the numerical range and the basis ordering should be stated in the caption to allow direct comparison with the ideal target states.
Simulated Author's Rebuttal
We thank the referee for their positive evaluation of our manuscript and for recommending minor revision. We are pleased that the experimental demonstration of the (2,3) quantum secret sharing protocol, the achieved fidelities above the no-cloning bound, and the identified secure parameter regime against dishonest players were viewed as a concrete milestone for multipartite quantum communication in superconducting hardware.
Circularity Check
No significant circularity: experimental demonstration
full rationale
The manuscript reports an experimental implementation of a (2,3) quantum secret sharing protocol using microwave two-mode squeezed states in a tripartite superconducting network. Central results are measured state fidelities exceeding the no-cloning bound F_nc=2/3, supported by tomography, reconstruction procedures, and noise characterization. Security bounds are derived from measured entanglement and noise levels rather than from any self-referential fit or ansatz. No derivation chain exists that reduces predictions or uniqueness claims to the paper's own inputs by construction; the work is self-contained against external benchmarks such as the asymptotic no-cloning threshold.
Axiom & Free-Parameter Ledger
axioms (1)
- standard math Quantum no-cloning theorem implies a fidelity threshold of 2/3 for secure secret sharing
read the original 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 $n$ players. Using microwave two-mode squeezed states as an entanglement resource, we experimentally implement a QSS protocol with $n = 3$, where a subset of at least $k = 2$ players must collaborate to faithfully reconstruct the original secret state. We demonstrate reconstructed-state fidelities that surpass the asymptotic no-cloning threshold of $F_\textrm{nc} = 2/3$ 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.
Figures
discussion (0)
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