Scalable generation of massive Schrödinger cat states via quantum tunnelling

Nature Physics (2026)Cite this article Massive objects in spatial superposition may provide insights into the interplay between quantum mechanics and gravity. Cold-atom interferometers offer a promising platform due to extended matter-wave coherence times and precise controllability. However, high-mass spatial superpositions beyond single atoms have yet to be generated in such setups. Here we report the scalable realization of high-mass spatial entanglement via the quantum tunnelling of ultracold atoms in optical lattices. We observe the coherent tunnelling of bound clusters, forming a composite object with a mass of 608 AMU. Full control of the model parameters allows us to mitigate the usual suppression of tunnelling with increasing mass. Furthermore, we construct an interferometer to certify the entanglement and use spatially distributed Schrödinger cat states to perform quantum-enhanced measurements. 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Halimeh, P. Hauke, S. Jochim, X. J. Liu, J.-W. Pan, B. Wu, H.-Z. Zhao, Q. Zhou, P. Zoller and our colleagues at SUSTech for insightful discussions. This work is supported by the National Key R&D Program of China (grant number 2022YFA1405800), NSFC (grant number 12274199), Shenzhen Science and Technology Program (grant number KQTD20240729102026004), Guangdong Major Project of Basic and Applied Basic Research (grant number 2023B0303000011) and Guangdong Provincial Quantum Science Strategic Initiative (grant numbers GDZX2204003, GDZX2303002, GDZX2304006 and GDZX2405006).These authors contributed equally: Han Zhang, Yong-Kui Wang, Yi Zheng.State Key Laboratory of Quantum Functional Materials, Department of Physics and Guangdong Basic Research Center of Excellence for Quantum Science, Southern University of Science and Technology, Shenzhen, ChinaHan Zhang, Yong-Kui Wang, Yi Zheng, Hai-Tao Bai & Bing YangQuantum Science Center of Guangdong-Hong Kong-Macao Greater Bay Area, Shenzhen, ChinaHan Zhang & Bing YangSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarSearch author on:PubMed Google ScholarB.Y. conceived, designed and supervised the experiment. B.Y., Y.-K.W., H.Z., Y.Z. and H.-T.B. built the apparatus. H.Z., Y.Z., B.Y. and Y.-K.W. performed the experiments and analysed the data. B.Y. and H.Z. wrote the paper, with input from all authors.Correspondence to Bing Yang.The authors declare no competing interests.Nature Physics thanks Simon Haine and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Peer reviewer reports are available.Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.Supplementary Figs. 1–10, Table 1 and Discussion.Statistical source data for Fig. 1.Statistical source data for Fig. 2.Statistical source data for Fig. 3.Statistical source data for Fig. 4.Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.Reprints and permissionsZhang, H., Wang, YK., Zheng, Y. et al. Scalable generation of massive Schrödinger cat states via quantum tunnelling. Nat. Phys. (2026). https://doi.org/10.1038/s41567-026-03281-9Download citationReceived: 26 July 2025Accepted: 02 April 2026Published: 11 May 2026Version of record: 11 May 2026DOI: https://doi.org/10.1038/s41567-026-03281-9Anyone you share the following link with will be able to read this content:Sorry, a shareable link is not currently available for this article. Provided by the Springer Nature SharedIt content-sharing initiative