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Reply to: Experiments implementing small commuting models lack gravitational features

Nature volume 643, pages E20–E23 (2025)Cite this article

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The Original Article was published on 23 July 2025

replying to: B. Kobrin et al. Nature https://doi.org/10.1038/s41586-025-08939-7 (2025).

In their Comment, Kobrin et al.1 argue that the model experimentally implemented in our original article2 does not exhibit features consistent with a dual gravitational interpretation of wormhole dynamics. The process in ref. 2 consists of a two-sided system coupled by a precisely timed interaction that teleports two fermions, ψ1 and ψ2. We emphasize that it is meaningful to ask only about the interpretation of particular processes, here the two-sided teleportation; asking whether the Hamiltonian itself is ‘gravitational’ is not a meaningful question. Indeed the Sachdev–Ye–Kitaev (SYK) Hamiltonian, when all possible processes are examined, does not have a useful or weakly coupled gravity description. Only certain low-temperature correlation functions are dominated by the Schwarzian mode; the full theory contains many other interacting light fields and string-like corrections. The dual of the double-scaled SYK may have a discrete space, among many not standard gravitational effects. In understanding the holographic interpretation presented in ref. 2, it is expected that many processes applied to the learned Hamiltonian do not have a gravitational description, despite a traversable wormhole interpretation existing for the two-sided process.

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Fig. 1: Thermalization and operator growth.
Fig. 2: Size winding of individual fermions.
Fig. 3: Behaviour of a perturbed Hamiltonian.

References

  1. Kobrin, B., Schuster, T. & Yao, N. Y. Experiments implementing small commuting models lack gravitational features. Nature https://doi.org/10.1038/s41586-025-08939-7 (2025).

  2. Jafferis, D. Traversable wormhole dynamics on a quantum processor. Nature 612, 51–55 (2022).

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  3. Maldacena, J. & Qi, X.-L. Eternal traversable wormhole. Preprint at https://arxiv.org/abs/1804.00491 (2018).

  4. Lykken, J. D. et al. Long-range wormhole teleportation. Preprint at https://arxiv.org/abs/2405.07876 (2024).

  5. Gao, P. & Jafferis, D. L. A traversable wormhole teleportation protocol in the SYK model. J. High. Energy Phys. 2021, 97 (2021).

    Article  MathSciNet  MATH  Google Scholar 

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Acknowledgements

This work is supported by the Department of Energy, Office of High Energy Physics through QuantISED programme grant SC0019219 on Quantum Communication Channels for Fundamental Physics. This manuscript has been authored by the Fermi Research Alliance, under contract no. DE-AC02-07CH11359 with the US Department of Energy, Office of Science, Office of High Energy Physics. S.I.D. is partially supported by the Brinson Foundation.

Author information

Authors and Affiliations

  1. Center for the Fundamental Laws of Nature, Harvard University, Cambridge, MA, USA

    Daniel Jafferis & David K. Kolchmeyer

  2. Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, MA, USA

    Alexander Zlokapa

  3. Division of Physics, Mathematics and Astronomy, Caltech, Pasadena, CA, USA

    Alexander Zlokapa, Samantha I. Davis & Maria Spiropulu

  4. Alliance for Quantum Technologies (AQT), California Institute of Technology, Pasadena, CA, USA

    Alexander Zlokapa, Samantha I. Davis & Maria Spiropulu

  5. Google Quantum AI, Venice, CA, USA

    Alexander Zlokapa & Hartmut Neven

  6. Fermilab Quantum Institute, Fermi National Accelerator Laboratory, Batavia, IL, USA

    Joseph D. Lykken

Authors
  1. Daniel Jafferis
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  2. Alexander Zlokapa
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  3. Joseph D. Lykken
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  4. David K. Kolchmeyer
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  5. Samantha I. Davis
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  7. Maria Spiropulu
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Contributions

J.D.L. worked on the theoretical calculations, computational aspects and simulations. D.J. worked on all theoretical aspects and the validation of the wormhole dynamics. Graduate student D.K.K. worked on theoretical aspects and calculations of the chord diagrams. Graduate student S.I.D. worked on the computations and simulation. Graduate student A.Z. worked on all theory and computational aspects, the learning methods and the validation results. H.N. reviewed all the validation results. M.S. is the lead principal investigator of the QCCFP Consortium Project and worked on all aspects of the research and the manuscript together with all authors. N. Lauk has taken a position at Photonic and did not work on this Reply.

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Correspondence to Maria Spiropulu.

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Jafferis, D., Zlokapa, A., Lykken, J.D. et al. Reply to: Experiments implementing small commuting models lack gravitational features. Nature 643, E20–E23 (2025). https://doi.org/10.1038/s41586-025-08995-z

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