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Global topological protection of entanglement in integrated photonic quantum walks

Liat Nemirovsky-Levy1, Yonatan Plotnik1, Alexander Palatnik1, Mark Lyubarov1, Ohad Segal2, Yaron Oz3, and Mordechai Segev1,2,*

  • 1Physics Department and Solid-State Institute, Technion, Haifa 3200003, Israel
  • 2Department of Electrical Engineering, Technion, Haifa 3200003, Israel
  • 3School of Physics and Astronomy, Tel-Aviv University, Tel-Aviv 69978, Israel

  • *Contact author: msegev@technion.ac.il
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Phys. Rev. Research 8, 033215 – Published 21 August, 2026

DOI: https://doi.org/10.1103/3nkp-m3w3

Abstract

Photon entanglement is a fundamental resource for quantum technologies, yet it is extremely fragile especially in large quantum circuitry, which is necessary for quantum information processing and computing. We propose an integrated scheme for direct topological protection of entanglement, enabling robust transport of entangled photonic states, even when the photon dynamically evolves during propagation. Our platform relies on a two-dimensional discrete-time quantum walks in synthetic dimensions, supporting topological edge states at the interface between distinct domains. Thus far, in all previous approaches for exploiting topology to protect entanglement, the protection was linked to the position of the photon in the actual structure. In contrast, our scheme relies on a synthetic temporal dimension (time bins) where the entangled state is always reproduced, despite fluctuations or variations that may emerge in the system. Thus, our scheme provides precise temporal control important for synchronization and timing in quantum computation. By suppressing phase-sensitive errors—the most critical noise source in photonic platforms—our approach can lower the physical error rate below fault-tolerance thresholds and reduce the overhead typically required for scalable quantum information processing. The robustness to errors arises from the fact that the entangled state is preserved through correlations in the synthetic (temporal) dimension. As a result, we ensure that at specific designated times, the emergent state faithfully reproduces the initial entangled state, despite the photon having taken any dynamically evolving paths. This approach establishes a robust framework for directly protecting entanglement.

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Phys. Rev. Research 8, 033215– Published 21 August, 2026
  • Received 7 March 2026
  • Accepted 23 July 2026
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Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.

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