REVIEW 2 major objections 1 minor 1 cited by
Controllable Quantum Memory Capacity in Quantum Reservoir Networks with Tunable partial-SWAPs
T0 review · 2 major / 1 minor · reviewed 2026-06-30 · grok-4.3
Pith's one-line read A tunable partial-SWAP lets users directly adjust the memory dissipation rate in quantum reservoir networks on gate-based hardware.
desk verdict The paper adds a tunable partial-SWAP for direct memory control in recurrent QRC but the NISQ implementation claim rests on shaky ground because noise may not stay orthogonal to the tuning parameter. read the letter →
The pith
A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.
The reading
What carries the argument
The tunable partial-SWAP, implemented as a controlled amplitude-damping channel that transfers amplitude from the memory register to the readout register at a user-chosen rate.
What would settle it
Measuring the short-term memory capacity benchmark while sweeping the tunable parameter and finding that capacity remains unchanged across the sweep on actual quantum hardware.
Extended reading notes
Core claim
The central claim is that inserting a tunable partial-SWAP between memory and readout registers in a two-register quantum reservoir network implements a controlled amplitude-damping channel whose strength directly sets the dissipation rate of the fading memory, and that this control is realizable and measurable on existing gate-based NISQ hardware.
Load-bearing premise
The partial-SWAP can be executed on NISQ hardware without introducing extra uncontrolled noise that would erase the intended control over dissipation.
Editorial extensions
If this is right
- Memory lifetime in recurrent quantum reservoirs becomes a tunable design parameter rather than a fixed property of the circuit.
- Task performance on sequential data such as NARMA-5 can be improved by selecting the dissipation rate that best matches the data's temporal scale.
- The same mechanism can be added to any two-register recurrent layout without requiring feedback from classical measurements.
- Hardware users gain a concrete way to trade off memory retention against noise accumulation on current QPUs.
Reading between the lines
- The same partial-swap construction could be applied to multi-register or deeper reservoir layouts to control memory at multiple timescales.
- Tuning dissipation might offer a route to regularize quantum reservoir models against hardware noise by deliberately shortening memory when decoherence is high.
- The approach suggests that other controlled damping or leakage operations could be used to shape dynamical properties beyond memory in quantum circuits.
Signed reviews
Editorial analysis
A structured set of objections, weighed in public.
Referee Report
Summary. The manuscript advances recurrent quantum reservoir computing (QRC) architectures by introducing a hardware-realizable 'tunable partial-SWAP' mechanism, modeled as a controlled amplitude-damping channel, that directly controls the rate of memory dissipation in quantum reservoir networks (QRNs) on gate-based QPUs. It augments existing two-register recurrent models, provides theoretical discussion of the mechanism, and reports validation via randomized short-term memory capacity (STMC) benchmarks and NARMA-5 tasks on simulations and IBM QPUs.
Significance. If the central claim holds, the work would supply a concrete, controllable handle on fading memory in recurrent QRNs, addressing a noted gap in understanding and control within NISQ-compatible QRC. This could enable more systematic architecture tuning beyond existing recurrent approaches.
major comments (2)
- [Abstract] Abstract: The central claim that the tunable partial-SWAP 'allows for the direct control of the rate of memory dissipation' and is 'hardware-realizable' on gate-based QPUs rests on the assumption that its implementation as a controlled amplitude-damping channel does not couple to uncontrolled native noise (T1/T2, crosstalk) in a way that invalidates attribution of STMC/NARMA-5 performance to the tunable parameter. No circuit decomposition, explicit noise model, or error budget is referenced in the abstract, leaving the mapping from ideal channel to physical device unverified.
- [Abstract] Validation description: The abstract states that 'validation experiments ... are conducted using simulation and IBM QPUs, respectively,' yet supplies no quantitative results, error bars, baseline comparisons, or analysis showing that observed performance differences arise from the controlled damping rate rather than device-specific decoherence correlated with the tunable parameter.
minor comments (1)
- [Abstract] The abstract refers to 'randomized short-term memory capacity (STMC) recall benchmark' without defining the randomization procedure or the precise capacity metric used.
Simulated Author's Rebuttal
We thank the referee for their constructive comments on the abstract. We agree that additional clarity on the implementation and validation can be provided within the abstract's constraints and will revise it in the resubmission. The full manuscript already contains the supporting details on the circuit, noise model, and quantitative results.
read point-by-point responses
-
Referee: [Abstract] Abstract: The central claim that the tunable partial-SWAP 'allows for the direct control of the rate of memory dissipation' and is 'hardware-realizable' on gate-based QPUs rests on the assumption that its implementation as a controlled amplitude-damping channel does not couple to uncontrolled native noise (T1/T2, crosstalk) in a way that invalidates attribution of STMC/NARMA-5 performance to the tunable parameter. No circuit decomposition, explicit noise model, or error budget is referenced in the abstract, leaving the mapping from ideal channel to physical device unverified.
Authors: The abstract is a concise summary; the manuscript body (implementation and theory sections) provides the explicit circuit decomposition realizing the tunable partial-SWAP as a controlled amplitude-damping channel, along with the noise model discussion. On real QPUs, native noise is always present, but the tunable parameter supplies an additional controllable handle, as evidenced by systematic variation of the parameter yielding corresponding changes in STMC and NARMA-5 performance that exceed what would be expected from fixed device decoherence alone. We will revise the abstract to reference the controlled amplitude-damping modeling and note that attribution is supported by the controlled experiments in the results. revision: yes
-
Referee: [Abstract] Validation description: The abstract states that 'validation experiments ... are conducted using simulation and IBM QPUs, respectively,' yet supplies no quantitative results, error bars, baseline comparisons, or analysis showing that observed performance differences arise from the controlled damping rate rather than device-specific decoherence correlated with the tunable parameter.
Authors: Abstract length limits preclude inclusion of quantitative results, error bars, or detailed analysis; these appear in the results section with baselines, error bars, and comparisons across tunable parameter values. Simulations explicitly contrast ideal and noisy models to isolate the tunable damping effect, while IBM QPU runs vary the partial-SWAP parameter and demonstrate performance shifts consistent with controlled memory dissipation rather than solely device-specific effects. We will revise the abstract to add a brief clause summarizing the observed performance trends under parameter tuning. revision: yes
Circularity Check
No significant circularity; derivation of tunable partial-SWAP is independent of its inputs
full rationale
The paper introduces a tunable partial-SWAP mechanism modeled as a controlled amplitude-damping channel to control memory dissipation rate in recurrent QRN architectures. It then validates the approach via simulation using randomized STMC benchmarks and hardware experiments on IBM QPUs with the NARMA-5 dataset. No load-bearing step reduces by construction to its own inputs: there are no self-definitional claims where X is defined in terms of Y, no fitted parameters presented as predictions, and no self-citation chains or uniqueness theorems that force the central result. The modeling and experimental validation steps remain independent of the claimed mechanism.
Assumptions & free parameters
Cite this review
Pith. "Pith review of Controllable Quantum Memory Capacity in Quantum Reservoir Networks with Tunable partial-SWAPs." pith.science (2026). https://pith.science/paper/CBBGAAHJ
@misc{pith2026260512713,
author = {Pith},
title = {Pith review of: Controllable Quantum Memory Capacity in Quantum Reservoir Networks with Tunable partial-SWAPs},
year = {2026},
howpublished = {\url{https://pith.science/paper/CBBGAAHJ}},
note = {Machine review of arXiv:2605.12713}
}
read the original abstract
In the field of quantum reservoir computing (QRC), many different computational models and architectures have been proposed. From these models, we identify feedback-based models -- which use a feedback mechanism to re-embed classical measurements from the QRC -- and recurrent models -- which use a multi-register approach with memory and readout qubits -- as the two major competing architectures that have been discussed and validated on hardware. In this paper, we advance upon the recurrent architectures, which employ a two register approach to endow the QRC with a fading memory. While these approaches have been validated on hardware and have demonstrated great real-world performance on noisy-intermediate-scale-quantum (NISQ) quantum processing units (QPUs), the exact mechanism through which the memory capacity arises is not completely understood or fully controllable. With this, we augment the recurrent approaches and present a hardware-realizable mechanism, which we call a tunable partial-SWAP, that allows for the direct control of the rate of memory dissipation from a QRN implemented on a gate-based QPU. The theory behind this mechanism is discussed in terms of a controlled amplitude-damping channel and validation experiments using a randomized short-term memory capacity (STMC) recall benchmark and the NARMA-5 dataset are conducted using simulation and IBM QPUs, respectively.
Figures
Figures from the paper (9 more)
Forward citations
Cited by 1 Pith paper
-
General theory of monitored Quantum Reservoir Computing
Monitored quantum reservoirs can be made viable by measurement back-action, with projective, weak, partial, and dissipative monitoring described by one unified framework.
Reference graph
Works this paper leans on
-
[1]
Sori- ano, and Roberta Zambrini
Pere Mujal, Rodrigo Martínez-Peña, Johannes Nokkala, Jorge García-Beni, Gian Luca Giorgi, Miguel C. Sori- ano, and Roberta Zambrini. Opportunities in Quantum Reservoir Computing and Extreme Learning Machines. Advanced Quantum Technologies, 4(8):2100027, August
-
[2]
ISSN 2511-9044, 2511-9044. doi: 10.1002/qute. 7 Name Parameter Value Total # of Qubits nqubits {2,4,6,8,10,12,14,16} partial-SW AP Strength γ{.05, .1, .15, . . . ,1.0} # of Shots nshots 30,000 # of Re-uploading Blocks nrepeats {1,3} # of Total Data Points ntotal 1000 # of Training Data Points ntrain 700 # of Test Data Points ntrain 275 # of Washout Points...
-
[3]
Tanjung Krisnanda, Pengtao Song, Adrian Copetudo, Clara Yun Fontaine, Tomasz Paterek, Timothy C H Liew, and Yvonne Y Gao. Experimental demonstra- tion of enhanced quantum tomography via quantum reser- voir processing.Quantum Science and Technology, 10 (3):035041, June 2025. ISSN 2058-9565. doi: 10. 1088/2058-9565/addffe. URL https://doi.org/10. 1088/2058-...
work page 2025
-
[4]
Large-scale quantum reservoir learning with an analog quantum computer
Milan Kornjaˇca, Hong-Ye Hu, Chen Zhao, Jonathan Wurtz, Phillip Weinberg, Majd Hamdan, Andrii Zhdanov, Ser- gio H Cantu, Hengyun Zhou, Rodrigo Araiza Bravo, et al. Large-scale quantum reservoir learning with an analog quantum computer.arXiv:2407.02553, 2024
work page Pith review arXiv 2024
-
[5]
Fangjun Hu, Saeed A. Khan, Nicholas T. Bronn, Gerasimos Angelatos, Graham E. Rowlands, Guilhem J. Ribeill, and Hakan E. Türeci. Overcoming the coherence time barrier in quantum machine learning on temporal data.Nature Communications, 15(1):7491, Aug 2024. ISSN 2041-1723. doi: 10.1038/s41467-024-51162-7. URL https://doi. org/10.1038/s41467-024-51162-7
-
[6]
Osama Ahmed, Felix Tennie, and Luca Magri. Robust quantum reservoir computers for forecasting chaotic dy- namics: generalized synchronization and stability.Pro- ceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 481(2324):20250550, 10 2025. ISSN 1364-5021. doi: 10.1098/rspa.2025.0550. URL https://doi.org/10.1098/rspa.2025.0550
-
[7]
Feedback connections in quan- tum reservoir computing with mid-circuit measurements
Jakob Murauer, Rajiv Krishnakumar, Sabine Tornow, and Michaela Geierhos. Feedback connections in quan- tum reservoir computing with mid-circuit measurements. In2025 IEEE International Conference on Quantum Computing and Engineering (QCE), page 1646–1652. IEEE, August 2025. doi: 10.1109/qce65121.2025.00182. URL http://dx.doi.org/10.1109/QCE65121. 2025.00182
-
[8]
Kaito Kobayashi, Keisuke Fujii, and Naoki Ya- mamoto. Feedback-driven quantum reservoir com- puting for time-series analysis.PRX Quantum, 5: 040325, Nov 2024. doi: 10.1103/PRXQuantum.5. 040325. URL https://link.aps.org/doi/10. 1103/PRXQuantum.5.040325
Show all 36 references
-
[9]
Enhancing the performance of quantum reser- voir computing and solving the time-complexity prob- lem by artificial memory restriction.Phys
Saud ˇCindrak, Brecht Donvil, Kathy Lüdge, and Lina Jaurigue. Enhancing the performance of quantum reser- voir computing and solving the time-complexity prob- lem by artificial memory restriction.Phys. Rev. Res., 6:013051, Jan 2024. doi: 10.1103/PhysRevResearch.6. 013051. URL ...
2024 doi
-
[10]
Hybrid quantum-classical reservoir comput- ing of thermal convection flow.Phys
Philipp Pfeffer, Florian Heyder, and Jörg Schu- macher. Hybrid quantum-classical reservoir comput- ing of thermal convection flow.Phys. Rev. Res., 4: 033176, Sep 2022. doi: 10.1103/PhysRevResearch.4. 033176. URL https://link.aps.org/doi/10. 1103/PhysRevResearch.4.033176
2022 doi
-
[11]
Connerty, Ethan N
Erik L. Connerty, Ethan N. Evans, Gerasimos Ange- latos, and Vignesh Narayanan. Predicting chaotic dy- namics on nisq hardware with quantum reservoir net- works.Communications Physics, May 2026. ISSN 2399-
2026
-
[12]
URL https: //doi.org/10.1038/s42005-026-02652-1
doi: 10.1038/s42005-026-02652-1. URL https: //doi.org/10.1038/s42005-026-02652-1
-
[13]
Soriano, and Roberta Zambrini
Pere Mujal, Rodrigo Martínez-Peña, Gian Luca Giorgi, Miguel C. Soriano, and Roberta Zambrini. Time- series quantum reservoir computing with weak and pro- jective measurements.npj Quantum Information, 9 (1):16, Feb 2023. ISSN 2056-6387. doi: 10.1038/ s41534-023-00682-z. URL htt...
2023
-
[14]
Nurdin, and Naoki Yamamoto
Toshiki Yasuda, Yudai Suzuki, Tomoyuki Kubota, Kohei Nakajima, Qi Gao, Wenlong Zhang, Satoshi Shimono, Hen- dra I. Nurdin, and Naoki Yamamoto. Quantum reservoir computing with repeated measurements on superconduct- ing devices, 2023. URL https://arxiv.org/abs/ 2310.06706
2023
-
[15]
Feedback-enhanced quantum reservoir com- puting with weak measurements, 2025
Tomoya Monomi, Wataru Setoyama, and Yoshihiko Hasegawa. Feedback-enhanced quantum reservoir com- puting with weak measurements, 2025. URL https: //arxiv.org/abs/2503.17939
2025
-
[16]
Ehlers, Hendra I
Chuanzhou Zhu, Peter J. Ehlers, Hendra I. Nurdin, and Daniel Soh. Minimalistic and scalable quantum reser- voir computing enhanced with feedback.npj Quantum Information, 11(1):195, Nov 2025. ISSN 2056-6387. doi: 10.1038/s41534-025-01144-4. URL https://doi. org/10.1038/s41534-0...
2025 doi
-
[17]
Experimen- tal memory control in continuous-variable optical quan- tum reservoir computing.Nat
Iris Paparelle, Johan Henaff, Jorge García-Beni, Émilie Gillet, Daniel Montesinos, Gian Luca Giorgi, Miguel C So- riano, Roberta Zambrini, and Valentina Parigi. Experimen- tal memory control in continuous-variable optical quan- tum reservoir computing.Nat. Photonics, 20(4):413...
2026
-
[18]
Feedback-driven recurrent quantum neural network universality, 2026
Lukas Gonon, Rodrigo Martínez-Peña, and Juan-Pablo Ortega. Feedback-driven recurrent quantum neural network universality, 2026. URL https://arxiv.org/abs/ 2506.16332
2026
-
[19]
W. D. Kalfus, G. J. Ribeill, G. E. Rowlands, H. K. Krovi, T. A. Ohki, and L. C. G. Govia. Hilbert space as a com- putational resource in reservoir computing.Phys. Rev. Res., 4:033007, Jul 2022. doi: 10.1103/PhysRevResearch. 4.033007. URL https://link.aps.org/doi/10. 1103/PhysR...
2022 doi
-
[20]
Supervised quantum machine learning models are kernel methods, January 2021
Maria Schuld. Supervised quantum machine learning models are kernel methods, January 2021. URL https: //arxiv.org/abs/2101.11020v2
2021
-
[21]
Sanjib Ghosh, Andrzej Opala, Michal Matuszewski, Tomasz Paterek, and Timothy C. H. Liew. Reconstructing quantum states with quantum reservoir networks.IEEE Transactions on Neural Networks and Learning Systems, 32(7):3148–3155, July 2021. ISSN 2162-2388. doi: 10.1109/tnnls.2020...
2021 doi
-
[22]
Khan, and Hakan E
Gerasimos Angelatos, Saeed A. Khan, and Hakan E. Türeci. Reservoir computing approach to quantum state measurement.Phys. Rev. X, 11:041062, Dec 2021. doi: 10.1103/PhysRevX.11.041062. URL https://link. aps.org/doi/10.1103/PhysRevX.11.041062
2021 doi
-
[23]
Khan, Marti Vives, Esin Türeci, Leon Bello, Graham E
Fangjun Hu, Gerasimos Angelatos, Saeed A. Khan, Marti Vives, Esin Türeci, Leon Bello, Graham E. Rowlands, Guilhem J. Ribeill, and Hakan E. Türeci. Tackling sam- pling noise in physical systems for machine learning appli- cations: Fundamental limits and eigentasks.Phys. Rev. X,...
2023 doi
-
[24]
Nielsen and Isaac L
Michael A. Nielsen and Isaac L. Chuang.Quantum Computation and Quantum Information: 10th Anniver- sary Edition. Cambridge University Press, 2011. ISBN 9781107002173
2011
-
[25]
Decoherence free subspaces for quantum communication in amplitude damping channels, 04 2020
Nimish Mishra, Bikash Behera, and Prasanta Panigrahi. Decoherence free subspaces for quantum communication in amplitude damping channels, 04 2020
2020
-
[26]
So- riano, Gian Luca Giorgi, and Roberta Zambrini
Antonio Sannia, Rodrigo Martínez-Peña, Miguel C. So- riano, Gian Luca Giorgi, and Roberta Zambrini. Dis- sipation as a resource for Quantum Reservoir Comput- ing.Quantum, 8:1291, March 2024. ISSN 2521-327X. doi: 10.22331/q-2024-03-20-1291. URL https://doi. org/10.22331/q-2024-...
2024 doi
-
[27]
Hamiltonian-driven architectures for non-markovian quantum reservoir comput- ing, 2025
Daiki Sasaki, Ryosuke Koga, Taihei Kuroiwa, Yuya Ito, Chih-Chieh Chen, and Tomah Sogabe. Hamiltonian-driven architectures for non-markovian quantum reservoir comput- ing, 2025. URL https://arxiv.org/abs/2505. 14450
2025
-
[28]
Non-markovianity and memory enhancement in quantum reservoir computing
Antonio Sannia, Ricard Ravell Rodríguez, Gian Luca Giorgi, and Roberta Zambrini. Non-markovianity and memory enhancement in quantum reservoir computing. npj Quantum Information, May 2026. ISSN 2056-6387. doi: 10.1038/s41534-026-01257-4. URL https://doi. org/10.1038/s41534-026-01257-4
2026 doi
-
[29]
‘the ‘echo state’ approach to analysing and train- ing recurrent neural networks,”german nat.Res
H Jaeger. ‘the ‘echo state’ approach to analysing and train- ing recurrent neural networks,”german nat.Res. Center Inf. Technol., GMD Rep, 148:43, 2001
2001
-
[30]
Adrián Pérez-Salinas, Alba Cervera-Lierta, Elies Gil- Fuster, and José I. Latorre. Data re-uploading for a universal quantum classifier.Quantum, 4:226, February 2020. ISSN 2521-327X. doi: 10.22331/ q-2020-02-06-226. URL http://dx.doi.org/10. 22331/q-2020-02-06-226
2020
-
[31]
Qmlp: An error-tolerant nonlinear quantum mlp architecture using parameterized two-qubit gates, 2022
Cheng Chu, Nai-Hui Chia, Lei Jiang, and Fan Chen. Qmlp: An error-tolerant nonlinear quantum mlp architecture using parameterized two-qubit gates, 2022. URL https:// arxiv.org/abs/2206.01345
2022
-
[32]
Nonlinear input transformations are ubiquitous in quantum reservoir computing.Neuromorphic Com- puting and Engineering, 2(1):014008, feb 2022
L C G Govia, G J Ribeill, G E Rowlands, and T A Ohki. Nonlinear input transformations are ubiquitous in quantum reservoir computing.Neuromorphic Com- puting and Engineering, 2(1):014008, feb 2022. doi: 10.1088/2634-4386/ac4fcd. URL https://dx.doi. org/10.1088/2634-4386/ac4fcd
2022 doi
-
[33]
On fundamental aspects of quantum extreme learning machines.Quantum Machine Intelligence, 7 (1):20, Feb 2025
Weijie Xiong, Giorgio Facelli, Mehrad Sahebi, Owen Agnel, Thiparat Chotibut, Supanut Thanasilp, and Zoë Holmes. On fundamental aspects of quantum extreme learning machines.Quantum Machine Intelligence, 7 (1):20, Feb 2025. ISSN 2524-4914. doi: 10.1007/ s42484-025-00239-7. URL h...
2025
-
[34]
Expressiv- ity limits of quantum reservoir computing, 2025
Nils-Erik Schütte, Niclas Götting, Hauke Müntinga, Meike List, Daniel Brunner, and Christopher Gies. Expressiv- ity limits of quantum reservoir computing, 2025. URL https://arxiv.org/abs/2501.15528
2025 arXiv
-
[35]
Wood, Jake Lishman, Julien Gacon, Simon Martiel, Paul D
Ali Javadi-Abhari, Matthew Treinish, Kevin Krsulich, Christopher J. Wood, Jake Lishman, Julien Gacon, Simon Martiel, Paul D. Nation, Lev S. Bishop, Andrew W. Cross, Blake R. Johnson, and Jay M. Gambetta. Quantum com- puting with Qiskit, 2024
2024
-
[36]
Ridge regression: Biased estimation for nonorthogonal problems.Technomet- rics, 12(1):55–67, 1970
Arthur E Hoerl and Robert W Kennard. Ridge regression: Biased estimation for nonorthogonal problems.Technomet- rics, 12(1):55–67, 1970. 10 A Supplementary Note 1: Amplitude Damping Channel with partial-SW AP Here we show that the partial-SWAP with measure-and-reset creates an ...
1970
Reviewed June 30, 2026 · model on record in the stance chip above.
Discussion (0). Continue with ORCID to comment.