pith. sign in

arxiv: 2605.15869 · v1 · pith:GAC7DDSUnew · submitted 2026-05-15 · 🪐 quant-ph · cs.NI

HOPPER: A Hop-by-hop Entanglement Distribution Protocol for Asynchronous Quantum Networks

Claudio Cicconetti This is my paper

Pith reviewed 2026-05-20 18:51 UTC · model grok-4.3

classification 🪐 quant-ph cs.NI
keywords quantum networksentanglement distributionasynchronous protocolshop-by-hopmultiplexingebitsquantum memoriesquantum internet
0
0 comments X

The pith

HOPPER is an asynchronous hop-by-hop protocol that multiplexes concurrent ebit requests using only local node decisions in quantum networks.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper shows that both synchronous and asynchronous entanglement distribution have so far assumed serial operation, which wastes time in long networks when nodes hold multiple memory qubits. It examines the effects of allowing several ebit requests to run concurrently on the same path. For the asynchronous case it introduces HOPPER, in which each intermediate node independently decides how to allocate its local memories and when to forward entanglement attempts. Simulations indicate that this approach supports parallel requests and yields markedly higher throughput than a synchronous baseline under realistic latency conditions. The result matters because it removes a hidden serial bottleneck that would otherwise slow the quantum Internet applications that need many entangled pairs at once.

Core claim

HOPPER is a novel distribution protocol for asynchronous quantum networks in which intermediate nodes make autonomous and hop-by-hop decisions on the use of their local resources when establishing an ebit, enabling effective handling of multiple ebit requests in parallel with better performance than synchronous alternatives.

What carries the argument

HOPPER protocol, the hop-by-hop mechanism in which each node uses only local information to schedule and allocate multiple memory qubits across concurrent ebit requests without waiting for global synchronization.

If this is right

  • Concurrent ebit requests no longer block one another while waiting for serial completion across long distances.
  • Nodes can exploit multiple memory qubits for parallel work without requiring network-wide time slots.
  • Asynchronous local decisions produce higher delivery rates than time-slotted synchronous methods when latency is high.
  • Resource allocation at each hop scales directly with the number of available local memories.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • Applications that need several entangled pairs at the same time could see substantially shorter setup times.
  • Network designers could reduce the cost of global clocks or synchronization layers by relying on local decisions.
  • HOPPER could be combined with existing routing schemes to choose paths that support many simultaneous requests.
  • Real-device tests would reveal whether the modeled memory independence holds under actual hardware noise.

Load-bearing premise

Intermediate nodes have multiple independent memory qubits that can be allocated to concurrent requests without extra decoherence or control errors beyond the single-request case.

What would settle it

A simulation or experiment in which multiplexing several requests on the same nodes produces decoherence or control errors large enough to eliminate the throughput advantage over the serial or synchronous baseline.

Figures

Figures reproduced from arXiv: 2605.15869 by Claudio Cicconetti.

Figure 1
Figure 1. Figure 1: Example of a 4-node quantum network to illustrate the system model [PITH_FULL_IMAGE:figures/full_fig_p002_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: Comparison of synchronous (top) vs. asynchronous (bottom) ap [PITH_FULL_IMAGE:figures/full_fig_p003_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: Example of inconsistency of quantum memories at two nodes, A and [PITH_FULL_IMAGE:figures/full_fig_p004_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: Finite State Machine (FSM) of a quantum memory cell. [PITH_FULL_IMAGE:figures/full_fig_p004_4.png] view at source ↗
Figure 5
Figure 5. Figure 5: Sequence diagram of the procedure to create an ebit between end-nodes A and B via intermediate nodes R1, R2, and R3, all with three memory [PITH_FULL_IMAGE:figures/full_fig_p005_5.png] view at source ↗
Figure 6
Figure 6. Figure 6: Long-distance regime. Throughput with SYNC, with varying proba￾bility of successfully completing the local entanglement phase and quantum memory size (Q). (Γ), and number of memory cells per node depend on the specific experiment. Other relevant simulation parameters are reported in Table I. The simulator allows arbitrary network topologies, even if in this paper we only study linear chains, a.k.a. individ… view at source ↗
Figure 8
Figure 8. Figure 8: Long-distance regime. Comparison of throughput (left) and fidelity (right) between [PITH_FULL_IMAGE:figures/full_fig_p008_8.png] view at source ↗
Figure 9
Figure 9. Figure 9: Long-distance regime. Throughput and fidelity achieved by [PITH_FULL_IMAGE:figures/full_fig_p008_9.png] view at source ↗
read the original abstract

The quantum Internet relies on the ability to distribute entangled quantum bits (ebits) between quantum memories at the end nodes, to perform applications like blind or distributed quantum computing that are impossible if end nodes are connected via a classical, i.e., non-quantum network. This need creates new challenges due to the fragile nature of entanglement, which decoheres over short timescales and cannot be amplified, buffered, or retransmitted. Two broad categories of approaches have been proposed in the scientific literature to realize such an entanglement distribution in a given path: one relying on a synchronous time-slotted model, and another one where intermediate nodes interact asynchronously. However, both of them implicitly assume a serial operation, where one ebit is established and made available to the application on end nodes before creating a new one. This is inefficient in long-range networks, with high transmission latencies, if the intermediate nodes have multiple memory qubits that could be used in parallel. To overcome this limitation, in this paper, we study the implications of multiplexing concurrent ebit requests on the same quantum, for both synchronous and asynchronous operation. Furthermore, for the latter, we define a novel distribution protocol, called HOPPER, where the intermediate nodes make autonomous and hop-by-hop decisions on the use of their local resources when establishing an ebit. With numerical simulations, we show that HOPPER is effective in handling multiple ebit requests in parallel, and it exhibits significantly better performance than a synchronous alternative in different scenarios.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 2 minor

Summary. The manuscript proposes HOPPER, a hop-by-hop entanglement distribution protocol for asynchronous quantum networks that enables multiplexing of concurrent ebit requests across multiple memory qubits at intermediate nodes. It compares this asynchronous approach to synchronous time-slotted operation and uses numerical simulations to claim that HOPPER handles parallel requests effectively while exhibiting significantly better performance than the synchronous baseline across different scenarios.

Significance. If the performance advantages hold under realistic conditions, the protocol could improve throughput and reduce latency for entanglement distribution in long-range quantum networks by exploiting parallel memory usage, which is particularly relevant for applications like distributed quantum computing where serial operation is inefficient due to high transmission latencies.

major comments (2)
  1. [Simulation results and methodology] The central performance claims (throughput and latency advantages of HOPPER) rest on numerical simulations whose setup, parameter choices (e.g., number of memory qubits per node, transmission latency, decoherence timescale), and statistical validation are insufficiently described. This is load-bearing because the reported gains over the synchronous alternative depend directly on these modeling choices.
  2. [Network and hardware model] Network model: The simulations treat intermediate nodes as having multiple independent memory qubits allocatable in parallel with exactly the same per-qubit decoherence and control-error rates as the single-request case. If concurrent allocation introduces crosstalk, increased control overhead, or collective decoherence (common in hardware), the modeled advantages would shrink, especially on long paths where entanglement lifetime is binding.
minor comments (2)
  1. [Protocol description] Clarify the exact definition of the synchronous baseline protocol and how multiplexing is (or is not) applied to it, to ensure the comparison is apples-to-apples.
  2. [Abstract] Add a brief enumeration of the 'different scenarios' tested in the simulations (e.g., path length, request rate, memory count) already in the abstract or introduction for improved readability.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for their thoughtful and constructive review of our manuscript on HOPPER. The comments raise important points about simulation transparency and modeling assumptions that we will address to strengthen the paper. Below we respond point by point to the major comments.

read point-by-point responses

  1. Referee: [Simulation results and methodology] The central performance claims (throughput and latency advantages of HOPPER) rest on numerical simulations whose setup, parameter choices (e.g., number of memory qubits per node, transmission latency, decoherence timescale), and statistical validation are insufficiently described. This is load-bearing because the reported gains over the synchronous alternative depend directly on these modeling choices.

    Authors: We agree that additional detail on the simulation methodology is necessary for full reproducibility and to substantiate the reported performance gains. In the revised manuscript we will expand the simulation section to explicitly list all parameter values (including number of memory qubits per node, transmission latencies, decoherence timescales, and control-error rates), describe the event-driven simulator implementation, and report the number of independent runs together with statistical measures such as standard deviations or confidence intervals. These additions will clarify how the throughput and latency advantages of HOPPER over the synchronous baseline were obtained across the evaluated scenarios. revision: yes

  2. Referee: [Network and hardware model] Network model: The simulations treat intermediate nodes as having multiple independent memory qubits allocatable in parallel with exactly the same per-qubit decoherence and control-error rates as the single-request case. If concurrent allocation introduces crosstalk, increased control overhead, or collective decoherence (common in hardware), the modeled advantages would shrink, especially on long paths where entanglement lifetime is binding.

    Authors: Our model deliberately assumes independent memory qubits with identical per-qubit rates to isolate the protocol-level effects of asynchronous hop-by-hop multiplexing. This is a standard first-step abstraction in quantum-network protocol studies. We recognize that real devices may exhibit crosstalk or collective decoherence that could reduce the observed gains, particularly on long paths. In the revision we will add a dedicated paragraph in the network-model section that explicitly states these assumptions, discusses their potential impact on long-path performance, and qualifies the claims accordingly while noting that the core advantage of parallel resource allocation remains relevant even under moderate additional noise. revision: partial

Circularity Check

0 steps flagged

No significant circularity: protocol definition and simulation evaluation are independent of results

full rationale

The paper defines HOPPER as a novel hop-by-hop asynchronous protocol for multiplexing concurrent ebit requests, with decisions made locally at intermediate nodes. Numerical simulations then evaluate its performance relative to a synchronous baseline under stated assumptions about independent memory qubits and unchanged per-qubit decoherence rates. No derivation step reduces a claimed prediction or uniqueness result to a fitted parameter, self-citation chain, or ansatz imported from prior work by the same authors. The protocol specification and simulation model are presented as self-contained; performance claims rest on explicit modeling choices rather than equations that are true by construction. This is the normal case of an independent protocol proposal with external simulation validation.

Axiom & Free-Parameter Ledger

2 free parameters · 2 axioms · 0 invented entities

The paper rests on standard domain assumptions about entanglement fragility and on simulation-specific parameters for memory count, latency, and decoherence; no new physical entities are postulated.

free parameters (2)
  • number of memory qubits per intermediate node
    Chosen to enable parallel allocation; specific values used in simulations are not stated in the abstract.
  • transmission latency and decoherence timescale
    Standard quantum-network parameters that determine when an ebit is usable; values are implicit in the reported performance differences.
axioms (2)
  • domain assumption Entanglement decoheres over short timescales and cannot be amplified, buffered, or retransmitted.
    Invoked in the opening paragraph as the reason serial operation is inefficient.
  • domain assumption Intermediate nodes can make autonomous decisions using only local state.
    Core premise of the asynchronous model and of HOPPER.

pith-pipeline@v0.9.0 · 5793 in / 1474 out tokens · 91551 ms · 2026-05-20T18:51:23.609158+00:00 · methodology

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Reference graph

Works this paper leans on

29 extracted references · 29 canonical work pages

  1. [1]

    The road to quantum internet: Progress in quantum network testbeds and major demonstrations,

    J. Liu, T. Le, T. Ji, R. Yu, D. Farfurnik, G. Byrd, and D. Stancil, “The road to quantum internet: Progress in quantum network testbeds and major demonstrations,”Progress in Quantum Electronics, vol. 99, p. 100551, Jan. 2025

    work page 2025

  2. [2]

    Architectural Principles for a Quantum Internet,

    W. Kozlowski, S. Wehner, R. V . Meter, B. Rijsman, A. S. Cacciapuoti, M. Caleffi, and S. Nagayama, “Architectural Principles for a Quantum Internet,” RFC 9340, Mar. 2023

    work page 2023

  3. [3]

    Towards Blind Quantum Ma- chine Learning in Entanglement Networks,

    D. M. De Abreu and A. Abel ´em, “Towards Blind Quantum Ma- chine Learning in Entanglement Networks,” inProceedings of the 2nd Workshop on Quantum Networks and Distributed Quantum Computing. Coimbra Portugal: ACM, Sep. 2025, pp. 8–13

    work page 2025

  4. [4]

    Anonymous transmission in a noisy quantum network using the $W$ state,

    V . Lipinska, G. Murta, and S. Wehner, “Anonymous transmission in a noisy quantum network using the $W$ state,”Physical Review A, vol. 98, no. 5, p. 052320, Nov. 2018

    work page 2018

  5. [5]

    Appli- cation Scenarios for the Quantum Internet,

    C. Wang, A. Rahman, R. Li, M. Aelmans, and K. Chakraborty, “Appli- cation Scenarios for the Quantum Internet,” RFC 9583, Jun. 2024

    work page 2024

  6. [6]

    Demonstration of quantum network protocols over a 14-km urban fiber link,

    S. Kuceraet al., “Demonstration of quantum network protocols over a 14-km urban fiber link,”npj Quantum Information, vol. 10, no. 1, p. 88, Sep. 2024

    work page 2024

  7. [7]

    An operating system for executing applications on quantum network nodes,

    C. Delle Donneet al., “An operating system for executing applications on quantum network nodes,”Nature, vol. 639, no. 8054, pp. 321–328, Mar. 2025

    work page 2025

  8. [8]

    Deterministic remote entanglement using a chiral quantum interconnect,

    A. Almanaklyet al., “Deterministic remote entanglement using a chiral quantum interconnect,”Nature Physics, Mar. 2025

    work page 2025

  9. [9]

    Survivable Entanglement Path Provisioning for Quantum Networks Under Link Failures,

    E. Oki, M. Maeda, and R. Shiraki, “Survivable Entanglement Path Provisioning for Quantum Networks Under Link Failures,”IEEE Open Journal of the Communications Society, vol. 7, pp. 1699–1716, 2026

    work page 2026

  10. [10]

    Request Scheduling in Quantum Networks,

    C. Cicconetti, M. Conti, and A. Passarella, “Request Scheduling in Quantum Networks,”IEEE Transactions on Quantum Engineering, vol. 2, pp. 2–17, 2021

    work page 2021

  11. [11]

    Analytical Bounds for Nonasymptotic Asymmetric State Discrimination,

    J. L. Pereira, L. Banchi, and S. Pirandola, “Analytical Bounds for Nonasymptotic Asymmetric State Discrimination,”Physical Review Ap- plied, vol. 19, no. 5, p. 054030, May 2023

    work page 2023

  12. [12]

    Routing entanglement in the quantum internet,

    M. Pant, H. Krovi, D. Towsley, L. Tassiulas, L. Jiang, P. Basu, D. En- glund, and S. Guha, “Routing entanglement in the quantum internet,” npj Quantum Information, vol. 5, no. 1, p. 25, Dec. 2019

    work page 2019

  13. [13]

    Designing a quantum network protocol,

    W. Kozlowski, A. Dahlberg, and S. Wehner, “Designing a quantum network protocol,” inProceedings of the 16th International Conference on emerging Networking EXperiments and Technologies. Barcelona Spain: ACM, Nov. 2020, pp. 1–16

    work page 2020

  14. [14]

    The Quantum Internet (Technical Version),

    P. P. Rohdeet al., “The Quantum Internet (Technical Version),” Jan. 2025, arXiv:2501.12107 [quant-ph]

    work page arXiv 2025

  15. [15]

    Review of Distributed Quantum Computing: From single QPU to High Performance Quantum Computing,

    C. Barralet al., “Review of Distributed Quantum Computing: From single QPU to High Performance Quantum Computing,”Computer Science Review, vol. 57, p. 100747, Aug. 2025

    work page 2025

  16. [16]

    Heralded entanglement between solid-state qubits separated by three metres,

    H. Bernien, B. Hensen, W. Pfaff, G. Koolstra, M. S. Blok, L. Robledo, T. H. Taminiau, M. Markham, D. J. Twitchen, L. Childress, and R. Hanson, “Heralded entanglement between solid-state qubits separated by three metres,”Nature, vol. 497, no. 7447, pp. 86–90, May 2013

    work page 2013

  17. [17]

    Hardware-efficient quantum error correction via concatenated bosonic qubits,

    H. Puttermanet al., “Hardware-efficient quantum error correction via concatenated bosonic qubits,”Nature, vol. 638, no. 8052, pp. 927–934, Feb. 2025

    work page 2025

  18. [18]

    Performance of Quantum Networks Using Heterogeneous Link Architectures,

    K. S. Soon, N. Benchasattabuse, M. Hajdu ˇsek, K. Teramoto, S. Na- gayama, and R. Van Meter, “Performance of Quantum Networks Using Heterogeneous Link Architectures,” in2024 IEEE International Confer- ence on Quantum Computing and Engineering (QCE). Montreal, QC, Canada: IEEE, Sep. 2024, pp. 1914–1923

    work page 2024

  19. [19]

    Position Paper: On the Application of Recursive Inter-Network Architecture to the Future Quantum-Enabled Internet,

    J. Jord ´an-Parra, S. Gim ´enez-Ant´on, E. Carmona-Cejudo, M. Garcia- Romero, and E. Grasa, “Position Paper: On the Application of Recursive Inter-Network Architecture to the Future Quantum-Enabled Internet,” inICC 2024 - IEEE International Conference on Communications. Denver, CO, USA: IEEE, Jun. 2024, pp. 3628–3633

    work page 2024

  20. [20]

    Entanglement buffering with multiple quantum memories,

    A. G. I ˜nesta, B. Davies, S. Kar, and S. Wehner, “Entanglement buffering with multiple quantum memories,”npj Quantum Information, Feb. 2026

    work page 2026

  21. [21]

    An efficient protocol for the quantum private comparison of equality with W state,

    W. Liu, Y .-B. Wang, and Z.-T. Jiang, “An efficient protocol for the quantum private comparison of equality with W state,”Optics Commu- nications, vol. 284, no. 12, pp. 3160–3163, Jun. 2011

    work page 2011

  22. [22]

    Generation and detection of discrete-variable multipartite en- tanglement with multirail encoding in linear-optics networks,

    J.-Y . Wu, “Generation and detection of discrete-variable multipartite en- tanglement with multirail encoding in linear-optics networks,”Physical Review A, vol. 106, no. 3, p. 032437, Sep. 2022

    work page 2022

  23. [23]

    Quan- tum Repeaters for Quantum Communication,

    H. J. Briegel, J. I. Cirac, W. D ¨ur, G. Giedke, and P. Zoller, “Quan- tum Repeaters for Quantum Communication,” inEpistemological and Experimental Perspectives on Quantum Physics, D. Greenberger, W. L. Reiter, and A. Zeilinger, Eds. Dordrecht: Springer Netherlands, 1999, pp. 147–154

    work page 1999

  24. [24]

    An integrated space-to-ground quantum communi- cation network over 4,600 kilometres,

    Y .-A. Chenet al., “An integrated space-to-ground quantum communi- cation network over 4,600 kilometres,”Nature, vol. 589, no. 7841, pp. 214–219, Jan. 2021

    work page 2021

  25. [25]

    Entanglement generation in a quantum network at distance-independent rate,

    A. Patil, M. Pant, D. Englund, D. Towsley, and S. Guha, “Entanglement generation in a quantum network at distance-independent rate,”npj Quantum Information, vol. 8, no. 1, pp. 1–9, May 2022, number: 1

    work page 2022

  26. [26]

    A Modular Quantum Network Architecture for Integrating Network Scheduling with Local Program Execution,

    T. R. Beauchamp, H. Jirovsk ´a, S. Gauthier, and S. Wehner, “A Modular Quantum Network Architecture for Integrating Network Scheduling with Local Program Execution,”IEEE Transactions on Quantum Engineer- ing, pp. 1–31, 2025

    work page 2025

  27. [27]

    Asyn- chronous entanglement routing for the quantum internet,

    Z. Yang, A. Ghubaish, R. Jain, H. Shapourian, and A. Shabani, “Asyn- chronous entanglement routing for the quantum internet,”AVS Quantum Science, vol. 6, no. 1, p. 013801, Mar. 2024

    work page 2024

  28. [28]

    End-to-end entanglement request scheduling in quantum networks via topology- aware decision transformer,

    Y . Seok, I. Ullah, Y .-H. Han, C. Lee, and W. Lee, “End-to-end entanglement request scheduling in quantum networks via topology- aware decision transformer,”Journal of Optical Communications and Networking, vol. 18, no. 1, pp. 1–15, 2026

    work page 2026

  29. [29]

    An Asynchronous Transport Protocol for Quantum Data Networks,

    Y . Zhao, Y . Wang, E. Wang, H. Xu, L. Huang, and C. Qiao, “An Asynchronous Transport Protocol for Quantum Data Networks,”IEEE Journal on Selected Areas in Communications, pp. 1–1, 2024

    work page 2024