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Leveraging Qubit Loss Detection in Fault-Tolerant Quantum Algorithms

Gefen Baranes1,2,*,†, Madelyn Cain2,*, J. Pablo Bonilla Ataides2,*, Dolev Bluvstein2, Josiah Sinclair1, Vladan Vuletić1, Hengyun Zhou2,3, and Mikhail D. Lukin2,‡

  • *These authors contributed equally to this work.
  • †Contact author: gbaranes@mit.edu
  • ‡Contact author: lukin@physics.harvard.edu
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Phys. Rev. X 16, 011002 – Published 2 January, 2026

DOI: https://doi.org/10.1103/ycwc-3myc

Abstract

Qubit loss errors constitute a dominant source of noise in many quantum hardware systems, particularly in neutral-atom quantum computers. We develop a theoretical framework to effectively detect and correct loss errors in logical algorithms and leverage such loss information in decoding. Considering general quantum error correction codes and logical circuits, we introduce a delayed-erasure decoder for experimentally motivated error models which leverages information from delayed loss detection to accurately correct loss errors, even when the precise moment of the error is unknown. Using this decoder, we identify strategies for detecting and correcting loss errors based on the logical circuit structure. For deep circuits prior to logical measurement, we explore methods to integrate loss detection into syndrome extraction with minimal overhead, identifying optimal strategies depending on the qubit loss fraction in the noise and hardware capabilities. In contrast, we find that many key algorithmic subroutines involve frequent gate teleportation, shortening the circuit depth before logical measurement and naturally replacing qubits with no additional experimental overhead. We simulate this setting using a toy model algorithm for small-angle synthesis and find a significant performance improvement as the loss fraction increases. These results provide a path forward for advancing large-scale fault-tolerant quantum computation in systems with loss error detection.

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Popular Summary

Quantum computers hold the potential to transform science and technology, but their basic building blocks—quantum bits, or qubits—are extremely fragile. Among the most difficult errors to handle is qubit loss, in which qubits disappear during computation. This problem is significant in many leading architectures and is especially common in machines built from neutral atoms. Our work tackles this challenge in a new way. We show that many quantum algorithms already contain natural mechanisms for detecting and managing lost qubits, revealing that qubit loss is not necessarily a defect to suppress but rather a resource for error correction.

We systematically analyze how different quantum computing architectures can identify and replace lost qubits and introduce a new theoretical method, the delayed-erasure decoder, which can correct errors even when the precise time or location of the loss is unknown. Crucially, we demonstrate that widely used algorithmic components—including gate teleportation and similar subroutines—inherently support loss tolerance, reducing the need for complicated hardware-level fixes.

Our insights suggest a shift in how quantum hardware and algorithms should be codesigned. By exploiting the built-in loss-handling features of quantum algorithms themselves, we can simplify the construction of practical quantum computers and accelerate progress toward large-scale, fault-tolerant devices. This perspective opens new routes for designing error-corrected quantum processors capable of tackling real-world problems.

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Phys. Rev. X 16, 011002– Published 2 January, 2026
  • Received 10 April 2025
  • Revised 25 September 2025
  • Accepted 6 November 2025
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